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Effects of a 4-week combined sloped training program in young basketball players’ physical performance
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ORIGINAL ARTICLE
Effects of a 4-week combined sloped training program in young basketball players’ physical performance Effets d’un programme d’entraînement combiné en pente de 4 semaines sur la performance physique des jeunes joueurs de basketball B. Figueira a,b,∗, B. Gonc ¸alves b,c, E. Abade b,d, R. Paulauskas a,e, N. Masiulis a, J. Sampaio b,c a
Faculty of Sports Biomedicine, Lithuanian Sports University, Sporto g. 6, 44221, Kaunas, Lithuania Research Center in Sports Sciences, Health Sciences and Human Development, CIDESD, 5000-801, Vila Real, Portugal c Sport Sciences Department, Universidade de Trás-os-Montes e Alto Douro, 5000-801, Vila Real, Portugal d University Institute of Maia, ISMAI, 4475-690, Maia, Portugal e Education Academy, Vytautas Magnus University, Vilnius, Lithuania b
Received 12 June 2019; accepted 27 August 2019
KEYWORDS Basketball; Sprint; Neuromuscular power; Running slope; Youth players
∗
Summary Aim. — The aim of this study was to compare the effects of a 4-week combined sloped training program with a standard flat training program performed by basketball players. Methods. — A total of 31 male elite youth basketball players were randomly allocated into an experimental (SLOPE, n = 15, age 13.4 ± 0.4 y, height 168.8 ± 14.2 cm, weight 52.6 ± 12.7 kg) and control training group (FLAT, n = 16, age 12.9 ± 0.3 y, height 169.5 ± 9.3 cm, weight 56.2 ± 11.3 kg). A pre- to post-test design was used to explore the effects in performance variables. Results. — The comparison between groups showed moderate higher values in FLAT training group for standing height jump (differences in groups means: % [90% confidence intervals], −10.2% [−14.9% to −5.3%]) and reaction time (5.8% [1.3% to 10.5%]). On the other hand, SLOPE training promoted a small improve in anaerobic-alactic power (W/kg) (3.4% [−1.2% to 8.1%]).
Corresponding author. E-mail address: benfi[email protected] (B. Figueira).
https://doi.org/10.1016/j.scispo.2019.08.001 0765-1597/© 2019 Elsevier Masson SAS. All rights reserved.
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B. Figueira et al. The FLAT group presented small improvements in peak power (W), (−9.2% [−15.0% to −3.0%]) and moderate in relative peak power (W/kg) (−9.8% [−15.3% to −4.0%]). Power results suggested a more efficient movement pattern, probably due to a better propulsive phase supported by an improved ability to produce equivalent levels of force in a shorter period of time. Despite the identified benefits of combined uphill/downhill/flat training method, results suggest that young non-familiarize players need a progressive reduction of training load to optimize performance. These results represent important evidence into the planning guidelines of strength and conditioning coaches to support daily planning by choosing the most appropriate tasks to enhance players’ performance. © 2019 Elsevier Masson SAS. All rights reserved.
MOTS CLÉS Basketball ; Sprint ; Puissance neuromusculaire ; Plan incliné ; Jeunes joueurs
Résumé Objectifs. — Le but de cette étude était de comparer les effets d’un programme d’entraînement combiné en pente de 4 semaines avec un programme standard d’entraînement sur surface plate effectué par des joueurs de basketball. Méthodes. — Au total, 31 joueurs masculins de basketball de haut niveau ont été répartis aléatoirement en deux groupes : un groupe expérimental (SLOPE, n = 15, âge 13,4 ± 0,4 et taille 168,8 ± 14,2 cm, poids 52,6 ± 12,7 kg) et un groupe témoin (FLAT, n = 16, âge 12,9 ± 0,3 ans, taille 169,5 ± 9,3 cm, poids 56,2 ± 11,3 kg). Un plan pré-post-test a été utilisé pour explorer les effets dans les variables de performance. Résultats. — La comparaison entre les groupes a montré des valeurs modérément plus élevées dans le groupe d’entraînement FLAT pour le saut en hauteur (différences entre les moyennes des groupes : % [intervalles de confiance 90 %], −10,2 % [−14,9 % à −5,3 %]) et le temps de réaction (5,8 % 1,3 % à 10,5 %]). D’autre part, l’entraînement SLOPE a favorisé une légère amélioration de la puissance anaérobie-alactique (W/kg) (3,4 % [−1,2 % à 8,1 %]). Le groupe FLAT a présenté de légères améliorations de la puissance pic (W), (−9,2 % [−15,0 % à −3,0 %]) et de la puissance pic relative (−9,8 % [−15,3 % à −4,0 %]). Les résultats de puissance ont suggéré un modèle de mouvement plus efficace, probablement dû à une meilleure phase propulsive soutenue par une meilleure capacité à produire des niveaux de force équivalents sur une plus courte période de temps. Malgré les avantages identifiés de la méthode combinée d’entraînement ascendant/descendant/plat, les résultats suggèrent que les jeunes joueurs non familiarisés ont besoin d’une diminution transitoire de l’entraînement pour optimiser leur performance. Ces résultats apportent des informations importantes pour mieux planifier les entraînements en force et mieux les coordonner quotidiennement en choisissant des exercices plus appropriés pour améliorer la performance des joueurs. © 2019 Elsevier Masson SAS. Tous droits r´ eserv´ es.
1. Introduction The identification of main descriptors as well as the key performance variables in team sports are important elements of a proper performance measurement framework. Basketball is an invasion team sport based on intermittent highintensity activity, interspersed with periods of low intensity and/or recovery [1,2]. Despite the identified potential benefits from aerobic conditioning on players’ activity levels [3,4], the short-term efforts and the high intensity of some specific actions (e.g. rebound, dribble, shot and block) configure the main demands for the anaerobic metabolism as the primary energy pathway [5,6]. Previous research has reported that during Basketball games, players performed a mean of 105 high-intensity short duration bouts (2—6 seconds), occurring each attempt on average every 21 seconds [7]. Other studies quantified the sprint intensity during competitive games at about 15 m [8] and about 19 m with junior elite players [9]. In this sense, the ability to perform repeated sprints is suggested as a key factor for high level performance in basketball [10].
The use of different training approaches, such as sprintresisted, non-resisted-sprint and over speed-sprint are designed to improve the repeated sprint ability [11,12]. Thus, running on sloped surfaces is probably among the most widely used training methods to improve the speed [13]. The use of uphill and downhill sloping surfaces seems to be a useful method to enhance the associated kinematic variables despite being scarcely explored in the literature [14]. For instance, Paradisis and Cooke [15] showed that after 6 weeks of training under similar conditions, downhill slope of 3◦ increased the maximum running speed (MRS) in 1.1% and step rate in 2.3% and uphill slope did not induce significant changes. Other studies assessed the combination between uphill and downhill training (3◦ ) and reported improvements in MRS, step rate, contact time and step time of 4.3%, 4.3%, 5.1% and 3.9% respectively, when compared to horizontal training group [13]. Downhill running requires primarily eccentric contractions, performed by quadriceps muscles in order to control the rate of knee flexion against the force of gravity [16]. This eccentric work requires the muscular-tendon system
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Effects of combined sloped training on basketball players’ to stretch and absorb mechanical energy that will be temporarily stored as elastic energy and subsequently recovered during an immediate shortening contraction [17]. Moreover, several studies showed the connection between the hamstring action and the running speed increase, reflected in large amounts of produced horizontal forces [18]. The available research shows uphill and downhill training programmes promote additional neuromuscular adaptations that seems to positively affect speed capacity [19]. However, no available research has assessed the influence of different training programs using sloping surfaces in basketball physical youth performance profiles. Younger athletes may present different physical and physiological adaptations to the same training stimulus when compared to experienced players [20]. On the other hand, a considerable number of studies has showed that despite the younger age, training-induced gains may support the skill-acquisition phase on order to withstand the long-term athletic training demands [21]. Repeated-sprint ability appears to benefit from a combined implementation of different approaches, including different forms of training contents. Thus, combining two or more divergent training modes may provide beneficial adaptations in skeletal muscles [22]. Thus, the aim of this study was to compare the effects of a 4-week combined uphill and downhill training program and a flat training program performed by non-familiarized young basketball players with sloped training. It was hypothesised that: • the combination between uphill and downhill training will present a positive impact in athletes’ performance; • FLAT training stimulus will not produce significant changes that may result in greater benefits; • eccentric exercise performed by non-familiarize young players may lead to detrimental results in sprint ability.
2. Methods 2.1. Subjects A total of 31 male elite youth basketball players participated in the study and were randomized allocated into two groups: experimental group (SLOPE, n = 15, age 13.4 ± 0.4 y, height 168.8 ± 14.2 cm, weight 52.6 ± 12.7 kg, standing reach 219.3 ± 20.8 cm and training experience 5.5 ± 0.1 y); and control group (FLAT, n = 16, age 12.9 ± 0.3 y, height 169.5 ± 9.3 cm, weight 56.2 ± 11.3 kg, standing reach 220.2 ± 15.3 cm and training experience 5.3 ± 0.1y). All participants competed at elite youth level in Under 14 National Basketball Championship. All the participants were healthy, without muscular, neurological and tendinous injuries and did not attend any other physical activity during the training program. All players and their parents were informed about the research procedures, requirements, benefits and risks and their written consent was obtained before the study began. Additionally, players were informed that they were free to withdraw at any time without any penalty. The investigation was approved by the local Institutional Research Ethics Committee and conformed to the recommendations of the Declaration of Helsinki.
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2.2. Design A two-group parallel randomized, pre- to post-test design was used [23]. The training program was employed for both groups during 4 weeks, 3 sessions in a week consisting of 90 minutes per session with three alternating days per week in a total of twelve training sessions and two testing sessions (pre- and post-test). All sessions were performed under similar environment conditions (relative humidity ∼60%) and circumstances (from 11.00 to 12.30 h) on a cushioned porous acrylic sports outdoor surface. All training sessions started with a 20-min standard warmup, with a preliminary articular and muscular mobilization consisting of low-intensity running and a dynamic stretching workout. Following this period, a main workout was performed aiming to increase speed and power of players, including jumps, hops, bounds and basic sprint drills. Both groups performed the following drills: • double jumps maximizing the vertical and horizontal motion component (Foot contacts per workout = 20); • hops maximizing the repeated motion (Foot contact per workout = 30); • alternate-leg bounding exaggerated horizontal movements (Foot contact per workout = 30); • basic sprint drills including walking on toes, walking on heels, sprint arm action, leg cycling and drives, butt kicks and skips (foot contact per workout = 110). Each exercise was performed five times with passive recovery in between, with a work-rest interval ranging from 1:5 to 1:20 targeting an adequate recovery of ATP-PC system [24]. Both groups performed the same exercises during the week microcycle, however, the FLAT performed all training sessions using flat conditions, while the SLOPE used downhill (9◦ degrees), flat and uphill conditions (9◦ degrees) respectively on the first, second and third days of microcycle. The total number of repetitions and work-rest ratio was similar in both groups. The session ended with a 10-min standardized cool-down, which consisted of jogging and stretching exercises. None of the players were familiarized with over-speed training, and the respectively concentric and eccentric contractions.
2.3. Methodology 2.3.1. Anthropometric variables The assessment of anthropometric parameters was carried out twice: one day before the beginning of the protocol (pretest) and two days after the training program’s last session (post-test). Height was measured using a Martin anthropometer (GPM Siber-Hegner, Switzerland) with an accuracy of ±0.1 cm. Weight and fat mass of each participant were assessed using a body composition analyser (TBF-300, Tanita UK Ltd. Philpots Close, UK) with an accuracy of ±0.01 kg. Body mass index (BMI; kg/m2) was calculated from the adjusted height and weight indices for each athlete. Muscle/Fat Index was calculated from the adjusted muscle weight and fat weight indices for each athlete. Standing reach was assessed using a vertical jump-measuring device (Vertec, Gill Athletics, USA).
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xxx.e4 2.3.2. Hand grip The hand grip strength was assessed using a portable digital hand dynamometer (Jamar, EN- 120604) according to the protocol guidelines [25]. The testing protocol consisted of three isometric contractions for 5 seconds, on both hands, with a rest period of at least 60 seconds. The highest recorded value was used for the determination of maximal grip strength [25]. 2.3.3. Jump performance test Lower limb explosive power (W) was assessed using a vertical drop jump (DJ drop height = 0.20 m). Each basketball player performed a DJ test with an Optojump TM device (Microgate, Bolzano, Italy) used to measure the jump height (cm) and contact time (ms) as a proxy for a muscular stretch-shortening performance [26]. During DJ, players were advised to jump as high as possible with minimum contact time, with the hands fixated at the hips. Jumping height was calculated according to the flight time method [27]. 2.3.4. Respiratory volume The pulmonary function test was assessed using a Spirometer Pony FX (Cosmed Ltd., Italy). All players were informed about the instrument set-up and procedures. The protocol test consisted in perform the pulmonary function test for three times and the best of the three results were considered for record. 2.3.5. Margaria-Kalamen anaerobic alactic power test The Margaria-Kalamen stair climb measure the athlete’s lower body peak power [28]. The participants began the test at a starting line placed 5 meters from the first step. One timer was positioned on the 3rd step and a second timer was positioned on the 9th step. On the researcher’s signal, the participant ran from the 5-meter starting mark as fast as he could up the stairway taking the steps three at a time (3rd, 6th, 9th). The timers started recording when the participant hit the 3rd step and stopped recording when the participant stepped on the 9th step. The average time was taken from the two timers for each trial. The participant completed 3 trials with a 20-s rest period prior to the start of each trial and the best performance time was used. The anaerobic power was measured in watts and was the product of force (weight of participant) multiplied by distance (height of stairs) and acceleration due to gravity (9.81 m·sec−1), then divided by time (sec−1). This computation of anaerobic power in watts used the equation [29]: AnaerobicAlacticPower(watts) = (bodymass(kg) × distance(0.96 m) × 9.81m·sec − 1)/time(sec − 1).
2.3.6. Simple reaction test Simple Reaction test belongs to the Vienna Test System (VTS) SPORT (Schuhfried GmbH, Moedling, Austria). The system is composed of a portable computer coupled to a VTS response panel and software. Participants sat at approximately 50 cm from the computer screen, which was positioned about 15 cm in front of the response panel and at the same height. In the middle of the response panel was the black square
B. Figueira et al. button and 5 cm below was the sensor button. To respond to stimuli presented, the participants used the index finger of the preferred hand. The other hand was placed next to the response panel. Before the test the participants were given instructions and allowed time to practice (until they carried out 5 reruns correctly executed). VTS simple RT consisted of a yellow light shown as a visual stimulus that appeared on the screen at random intervals. The participant had to react as quickly as possible by pressing a square black button on the panel. While there was no stimulus shown the participant’s, finger remained on a sensor button. The parameter measured in test was the time lapse (ms) between the appearance of the stimulus on the screen and the finger leaving the sensor and pressing the black button. The errors in choice RT were not assessed due to low incidence (this circumstance happened in less than 1% of the cases and neither of the participants made the mistake more than twice). 2.3.7. Finger-tapping test The finger-tapping test is a neuropsychological test that examines motor function, specifically, motor speed and lateralized coordination. In this study, a single FTT (index finger) was employed. Each participant was seated comfortably in a chair 50 cm from the computer screen, and had a wrist support [30]. The participants were asked to tap a predetermined key on the keyboard repeatedly at the maximum rate possible for 10 s. The single FTT was conducted using a digital Finger Tapping Test system [31]. The system records and saves the tapping data on the hard drive of a computer for later analysis. 2.3.8. Hexagon agility test The Hexagon Agility Test measure the ability to move quickly while maintaining balance [32]. Given the signal, participant jumps forward over the line and returns to the center of the hexagon. Looking in the same direction, they will repeat the action on each side of the hexagon clockwise. The stopwatch will stop when he finishes three complete turns, and his feet are at the center of the hexagon again. The athlete has 5 min rest and then repeats the test. The time that was registered, was the better of his two attempts. A practice trial was allowed prior to recording scores to attenuate the possibility of a learning effect.
2.4. Statistical analysis A descriptive analysis was performed using means and standard deviations. To identify the possibly impair/improve effects of the intervention on players’ performance measures, the data were analysed with a specific spreadsheet for pre-post parallel group trial [33]. The effects were estimated in percent units through log-transformation and uncertainty in the estimate was expressed as 95% confidence limits. Smallest worthwhile differences were estimated from the standardized units multiplied by 0.2 and the probabilities were reported using the following scale: 25—75% possibly; 75—95% likely; 95—99% very likely; > 99% most likely [34]. Standardized (Cohen’s d) mean differences, and respective 90% confidence intervals were also computed as magnitude of observed effects, and, thresholds were 0.2,
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Effects of combined sloped training on basketball players’ Table 1
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Inferences for the FLAT vs. SLOPE intervention on players’ characteristics measures.
Variables
Height (cm) Weight (kg) BMI (kg/m2 ) Dyna R (kg) Dyna L (kg) Resp. vol (L) Musc. mass (kg) Fat mass (kg) Musc/fat index (a.u.) Stand height reach (cm)
Pre
Post
Pre
Post
Differences in means % [90% confidence intervals]
169.47 ± 9.35 56.22 ± 11.26 19.38 ± 2.26 33.27 ± 6.97 32.60 ± 5.80 3.77 ± 0.57 30.19 ± 7.10 6.03 ± 1.60 5.14 ± 1.20
169.77 ± 9.27 56.51 ± 11.23 19.44 ± 2.25 33.93 ± 6.64 31.67 ± 5.68 3.75 ± 0.56 30.21 ± 7.07 5.97 ± 1.65 5.25 ± 1.27
168.83 ± 14.23 52.63 ± 12.71 18.19 ± 1.75 29.73 ± 6.12 28.60 ± 6.16 3.61 ± 0.77 27.29 ± 6.68 5.41 ± 1.52 5.21 ± 1.25
169.10 ± 14.11 53.06 ± 12.97 18.27 ± 1.75 29.87 ± 5.78 29.87 ± 6.81 3.77 ± 0.89 27.65 ± 6.78 5.53 ± 1.50 5.12 ± 1.12
0.0 [−0.2 to 0.2] 0.2 [−0.4 to 0.8] 0.1 [−0.7 to 0.9] −1.6 [−7.1 to 4.2] 7.3 [0.7 to 14.3] 4.9 [0.6 to 9.3] 1.2 [0.4 to 2.1] 4.3 [−0.3 to 9.0] −3.1 [−7.1 to 1.1]
FLAT group
SLOPE group
220.20 ± 15.35 221.07 ± 15.23 219.33 ± 20.81 219.80 ± 20.08 −0.20 [−0.8 to 0.4]
Practical inferences Most like trivial Most like trivial Most like trivial Unclear Likely beneficial Possibly beneficial Most likely trivial Possibly harmful Possibly harmful Most like trivial
Figure 1 Standardized (Cohen) differences between control and experimental groups. Error bars indicate uncertainty in the true mean changes with 90% confidence intervals. BMI: body mass index.
trivial; 0.6, small; 1.2, moderate; 2.0, large; and > 2.0, very large [34].
3. Results Table 1 and Fig. 1 present the practical inferences and standardized Cohen’s d differences based on the pre-post parallel group trial analysis. Results showed different trends between both training methods. Overall, the SLOPE group
presented a small increase in left hand grip strength test (difference in means: % [90% CL], likely beneficial, 7.3% [0.7% to 14.3%] and respiratory volume (possibly beneficial, 4.9% [0.6% to 9.3%]) than FLAT group. Table 2 and Fig. 2 present the practical inferences and standardized Cohen’s d differences to performance variables based on the pre-post parallel group trial analysis. The power results presented an opposite trend between both training methods with the moderate improve results being
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Inferences for the FLAT vs. SLOPE intervention on players’ performance measures.
Stan heigh jump (cm) Drop jump (cm) Contact time (ms) Jump power (W) Jump power (Wkg) Ana Alacti power (W) Ana Alacti power (W/kg) Reaction time (ms) Taping test (s) Hexagon agility (s) 10s Peak (W) Peak (W/kg) Average (W) Average (W/kg)
Pre
Post
Pre
Post
Differences in means % [90% confidence intervals]
48.20 ± 5.29 42.00 ± 7.44 200.20 ± 26.62 1171.20 ± 256.01 20.95 ± 2.90 859.33 ± 160.16 15.36 ± 1.33 179.00 ± 16.49 75.93 ± 6.91 13.21 ± 1.88 699.27 ± 151.29 12.43 ± 1.70 583.67 ± 160.92 10.31 ± 1.88
52.27 ± 4.13 46.00 ± 7.51 192.07 ± 26.95 1331.33 ± 304.19 23.78 ± 4.66 882.00 ± 196.76 15.59 ± 1.312 176.13 ± 12.29 75.27 ± 6.50 11.62 ± 0.77 804.47 ± 236.22 14.11 ± 2.14 589.53 ± 187.10 10.29 ± 1.96
47.20 ± 5.72 42.20 ± 6.17 238.20 ± 35.22 923.07 ± 250.73 17.56 ± 2.61 714.27 ± 195.70 13.50 ± 1.39 182.20 ± 15.27 72.73 ± 6.67 14.37 ± 0.80 612.60 ± 180.29 11.59 ± 1.43 537.73 ± 161.50 10.16 ± 1.34
46.13 ± 6.01 43.53 ± 9.01 216.80 ± 41.85 1011.47 ± 225.18 19.30 ± 3.22 750.80 ± 204.46 14.16 ± 1.37 189.87 ± 15.00 72.40 ± 6.93 13.11 ± 0.74 634.00 ± 197.41 11.88 ± 1.72 554.87 ± 170.71 10.44 ± 1.55
−10.2 [−14.9 to −5.3] −6.8 [−15.8 to 3.2] −5.8 [−14.1 to 3.3] −2.4 [−12.0 to 8.1] −2.7 [−12.4 to 8.0] 3.3 [−1.4 to 8.1] 3.4 [−1.2 to 8.1] 5.8 [1.3 to 10.5] 0.3 [−2.3 to 3.1] 3.0 [−3.0 to 9.4] −9.2 [−15.0 to −3.0] −9.8 [−15.3 to −4.0] 3.0 [−3.6 to 10.1] 2.8 [−3.9 to 9.9]
FLAT group
SLOPE group
Practical inferences
Very likely harmful Unclear Unclear Unclear Unclear Likely trivial Possibly beneficial Likely harmful Unclear Unclear Likely harmful Very likely harmful Unlikely Unclear
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Variables
B. Figueira et al.
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Table 2
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Effects of combined sloped training on basketball players’
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Figure 2 Standardized (Cohen) differences between control and experimental groups. Error bars indicate uncertainty in the true mean changes with 90% confidence intervals.
presented by FLAT group in standing height jump (−10.2% [−14.9% to −5.3%]) and reaction time (5.8% [1.3% to 10.5%]). On the other hand, SLOPE group showed small improve results in anaerobic-alactic power (W/kg) (possibly beneficial, 3.4% [−1.2% to 8.1%]). Athlete’s lower body peak power assessed in cycle ergometer power during 10 seconds, the FLAT group presented small improvements in peak (W), (−9.2% [−15.0% to −3.0%]) and moderate in peak (W/kg) (−9.8% [−15.3% to −4.0%]).
4. Discussion This study aimed to compare the effects of a 4-week combined uphill/downhill/flat training program and a flat training program performed by young non-familiarized basketball players with sloped training. The results of the present study showed that FLAT training group presented moderate improvements in vertical capacity jump and reaction time, as well as in 10 s peak (W) and in peak (W/kg) when compared with SLOPE method.
Uphill running is a popular method to improve running speed performance, requiring an increase in the concentric contraction particularly of the vastus medialis, biceps femoris and gastrocnemius [35,36]. Still, running at a negative gradient (i.e. downhill) primarily requires eccentric contractions, performed by quadriceps muscles [16]. Moreover, several studies identified the effects of a combined uphill-downhill sprint training, showing an increase in maximum running speed (3.5%) and step frequency (3.4%), while flight time (4.3%) and contact time (3.3%) decreased [15]. Other studies quantified the effects of combined uphilldownhill sprint training and showed superior results when compared to a horizontal sprint training [13]. Training program exercises performed under slope conditions promoted a greater exposure to eccentric contraction. It is well known that eccentric actions induce greater muscle damage, mainly because of range of motion and muscle length [37], the type of muscular contraction and the torque generated during exercise [38]. In fact, during eccentric contractions, muscles are stretched and exposed to a
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xxx.e8 greater load than the force developed which may result in muscle micro lesions and acute impairments in performance [39]. On the other hand, high intensity eccentric training is associated with important physiological adaptations in contractile and non-contractile muscle elements [40] which may play an important role in chronic neuromuscular effects such as increased muscle growth and force production [41]. Likewise, the results presented by SLOPE group support to the influence of eccentric contractions performed at higher velocity. The strain placed on a muscle during eccentric contractions depends on the time in which the muscle is under tension and the total number of muscle contractions. Thus, contraction velocity is one of the key variables that affect the torque development and the magnitude of muscle damage [38]. Interestingly, it was already reported that when time under tension is equal, fast velocity during eccentric exercise induces greater muscle damage [42], mainly in untrained subjects as it was the case in this study. It is important to notice that the training program performed in this study aimed to increase speed capacity and power output. Therefore, jumps, hops, bounds and basic sprint drills were performed at high velocities, which mean that eccentric and high-speed actions were combined during training sessions. It is also reported in literature that unaccustomed eccentric exercise may induce greater acute muscle damage, soreness and force impairments [43]. As the players that participated in this study were not familiarized with eccentric training, the probability of increased fatigue due to the mechanical detrimental effects and consequent muscle soreness was high. Despite the identified benefits of uphill/downhill/flat combined stimulus, the results of present study showed a detrimental effect in performance variables in SLOPE compared to FLAT. The post evaluation moment was performed two days after the end of the training program. This means that there was not a progressive reduction of the training load (i.e. taper phase), a common approach used in team sports to reduce the physiological stress of training programs and optimize performance [44]. Literature focused under this scope shows that in the majority of the cases, a supercompensation of physical qualities is observed after a 7—10 days tapering phase such as in muscle torque, vertical jump capacity, sprint capacity [45] and repeated sprint ability [46]. Adding together, the non-familiarization with eccentric exercise and the absence of a taper phase resulted in significant decrements in performance immediately after the cessation of the training program, particularly in standing height jump and reaction time. The FLAT group showed moderate improvements in 10 s peak (W) and in peak (W/kg), SLOPE group also presented improvements, albeit smaller. Available research has shown a tendency to produce shorter concentric phase during downhill training [15]. Thus, this may suggest a more efficient movement pattern through a better propulsive phase and may help to understand our results, supported by an improved ability to produce the same levels of force in a shorter period of time [19]. Overall, the changes presented in left hand grip strength and in respiratory volume (see Table 1 and Fig. 1) are likely beneficial in SLOPE group when compared with FLAT group. However, when considering the pre-post changes, the effect of the 4 weeks seems to be trivial or unclear.
B. Figueira et al. The sample size in this study can be pointed as a limitation due to the training frequency of athletes, which results in problems to find population to apply a training programme with sloped characteristics as well as the duration of 4 weeks. However, present findings should stimulate investigators to examine this topic further.
5. Conclusion The present study showed than despite the identified benefits of combined uphill/downhill/flat training method, young non-familiarize players need a progressive reduction of training load to optimize performance. The results provided evidence that eccentric contractions performed at higher velocity induce greater acute muscle damage, increasing mechanical detrimental effects that significant affect the performance. On the other hand, the maturation status of young players may have affected some physical adaptations as well as the final programme outcomes. These results represent important evidence into the planning guidelines of strength and conditioning coaches to support daily planning by choosing the most appropriate tasks that can enhance players’ performance.
Disclosure of interest The authors declare that they have no competing interest.
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Effects of a 4-week combined sloped training program in young basketball players’ physical performance Effets d’un programme d’entraînement combiné en pente de 4 semaines sur la performance physique des jeunes joueurs de basketball B. Figueira a,b,∗, B. Gonc ¸alves b,c, E. Abade b,d, R. Paulauskas a,e, N. Masiulis a, J. Sampaio b,c a
Faculty of Sports Biomedicine, Lithuanian Sports University, Sporto g. 6, 44221, Kaunas, Lithuania Research Center in Sports Sciences, Health Sciences and Human Development, CIDESD, 5000-801, Vila Real, Portugal c Sport Sciences Department, Universidade de Trás-os-Montes e Alto Douro, 5000-801, Vila Real, Portugal d University Institute of Maia, ISMAI, 4475-690, Maia, Portugal e Education Academy, Vytautas Magnus University, Vilnius, Lithuania b
Received 12 June 2019; accepted 27 August 2019
KEYWORDS Basketball; Sprint; Neuromuscular power; Running slope; Youth players
∗
Summary Aim. — The aim of this study was to compare the effects of a 4-week combined sloped training program with a standard flat training program performed by basketball players. Methods. — A total of 31 male elite youth basketball players were randomly allocated into an experimental (SLOPE, n = 15, age 13.4 ± 0.4 y, height 168.8 ± 14.2 cm, weight 52.6 ± 12.7 kg) and control training group (FLAT, n = 16, age 12.9 ± 0.3 y, height 169.5 ± 9.3 cm, weight 56.2 ± 11.3 kg). A pre- to post-test design was used to explore the effects in performance variables. Results. — The comparison between groups showed moderate higher values in FLAT training group for standing height jump (differences in groups means: % [90% confidence intervals], −10.2% [−14.9% to −5.3%]) and reaction time (5.8% [1.3% to 10.5%]). On the other hand, SLOPE training promoted a small improve in anaerobic-alactic power (W/kg) (3.4% [−1.2% to 8.1%]).
Corresponding author. E-mail address: benfi[email protected] (B. Figueira).
https://doi.org/10.1016/j.scispo.2019.08.001 0765-1597/© 2019 Elsevier Masson SAS. All rights reserved.
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B. Figueira et al. The FLAT group presented small improvements in peak power (W), (−9.2% [−15.0% to −3.0%]) and moderate in relative peak power (W/kg) (−9.8% [−15.3% to −4.0%]). Power results suggested a more efficient movement pattern, probably due to a better propulsive phase supported by an improved ability to produce equivalent levels of force in a shorter period of time. Despite the identified benefits of combined uphill/downhill/flat training method, results suggest that young non-familiarize players need a progressive reduction of training load to optimize performance. These results represent important evidence into the planning guidelines of strength and conditioning coaches to support daily planning by choosing the most appropriate tasks to enhance players’ performance. © 2019 Elsevier Masson SAS. All rights reserved.
MOTS CLÉS Basketball ; Sprint ; Puissance neuromusculaire ; Plan incliné ; Jeunes joueurs
Résumé Objectifs. — Le but de cette étude était de comparer les effets d’un programme d’entraînement combiné en pente de 4 semaines avec un programme standard d’entraînement sur surface plate effectué par des joueurs de basketball. Méthodes. — Au total, 31 joueurs masculins de basketball de haut niveau ont été répartis aléatoirement en deux groupes : un groupe expérimental (SLOPE, n = 15, âge 13,4 ± 0,4 et taille 168,8 ± 14,2 cm, poids 52,6 ± 12,7 kg) et un groupe témoin (FLAT, n = 16, âge 12,9 ± 0,3 ans, taille 169,5 ± 9,3 cm, poids 56,2 ± 11,3 kg). Un plan pré-post-test a été utilisé pour explorer les effets dans les variables de performance. Résultats. — La comparaison entre les groupes a montré des valeurs modérément plus élevées dans le groupe d’entraînement FLAT pour le saut en hauteur (différences entre les moyennes des groupes : % [intervalles de confiance 90 %], −10,2 % [−14,9 % à −5,3 %]) et le temps de réaction (5,8 % 1,3 % à 10,5 %]). D’autre part, l’entraînement SLOPE a favorisé une légère amélioration de la puissance anaérobie-alactique (W/kg) (3,4 % [−1,2 % à 8,1 %]). Le groupe FLAT a présenté de légères améliorations de la puissance pic (W), (−9,2 % [−15,0 % à −3,0 %]) et de la puissance pic relative (−9,8 % [−15,3 % à −4,0 %]). Les résultats de puissance ont suggéré un modèle de mouvement plus efficace, probablement dû à une meilleure phase propulsive soutenue par une meilleure capacité à produire des niveaux de force équivalents sur une plus courte période de temps. Malgré les avantages identifiés de la méthode combinée d’entraînement ascendant/descendant/plat, les résultats suggèrent que les jeunes joueurs non familiarisés ont besoin d’une diminution transitoire de l’entraînement pour optimiser leur performance. Ces résultats apportent des informations importantes pour mieux planifier les entraînements en force et mieux les coordonner quotidiennement en choisissant des exercices plus appropriés pour améliorer la performance des joueurs. © 2019 Elsevier Masson SAS. Tous droits r´ eserv´ es.
1. Introduction The identification of main descriptors as well as the key performance variables in team sports are important elements of a proper performance measurement framework. Basketball is an invasion team sport based on intermittent highintensity activity, interspersed with periods of low intensity and/or recovery [1,2]. Despite the identified potential benefits from aerobic conditioning on players’ activity levels [3,4], the short-term efforts and the high intensity of some specific actions (e.g. rebound, dribble, shot and block) configure the main demands for the anaerobic metabolism as the primary energy pathway [5,6]. Previous research has reported that during Basketball games, players performed a mean of 105 high-intensity short duration bouts (2—6 seconds), occurring each attempt on average every 21 seconds [7]. Other studies quantified the sprint intensity during competitive games at about 15 m [8] and about 19 m with junior elite players [9]. In this sense, the ability to perform repeated sprints is suggested as a key factor for high level performance in basketball [10].
The use of different training approaches, such as sprintresisted, non-resisted-sprint and over speed-sprint are designed to improve the repeated sprint ability [11,12]. Thus, running on sloped surfaces is probably among the most widely used training methods to improve the speed [13]. The use of uphill and downhill sloping surfaces seems to be a useful method to enhance the associated kinematic variables despite being scarcely explored in the literature [14]. For instance, Paradisis and Cooke [15] showed that after 6 weeks of training under similar conditions, downhill slope of 3◦ increased the maximum running speed (MRS) in 1.1% and step rate in 2.3% and uphill slope did not induce significant changes. Other studies assessed the combination between uphill and downhill training (3◦ ) and reported improvements in MRS, step rate, contact time and step time of 4.3%, 4.3%, 5.1% and 3.9% respectively, when compared to horizontal training group [13]. Downhill running requires primarily eccentric contractions, performed by quadriceps muscles in order to control the rate of knee flexion against the force of gravity [16]. This eccentric work requires the muscular-tendon system
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Effects of combined sloped training on basketball players’ to stretch and absorb mechanical energy that will be temporarily stored as elastic energy and subsequently recovered during an immediate shortening contraction [17]. Moreover, several studies showed the connection between the hamstring action and the running speed increase, reflected in large amounts of produced horizontal forces [18]. The available research shows uphill and downhill training programmes promote additional neuromuscular adaptations that seems to positively affect speed capacity [19]. However, no available research has assessed the influence of different training programs using sloping surfaces in basketball physical youth performance profiles. Younger athletes may present different physical and physiological adaptations to the same training stimulus when compared to experienced players [20]. On the other hand, a considerable number of studies has showed that despite the younger age, training-induced gains may support the skill-acquisition phase on order to withstand the long-term athletic training demands [21]. Repeated-sprint ability appears to benefit from a combined implementation of different approaches, including different forms of training contents. Thus, combining two or more divergent training modes may provide beneficial adaptations in skeletal muscles [22]. Thus, the aim of this study was to compare the effects of a 4-week combined uphill and downhill training program and a flat training program performed by non-familiarized young basketball players with sloped training. It was hypothesised that: • the combination between uphill and downhill training will present a positive impact in athletes’ performance; • FLAT training stimulus will not produce significant changes that may result in greater benefits; • eccentric exercise performed by non-familiarize young players may lead to detrimental results in sprint ability.
2. Methods 2.1. Subjects A total of 31 male elite youth basketball players participated in the study and were randomized allocated into two groups: experimental group (SLOPE, n = 15, age 13.4 ± 0.4 y, height 168.8 ± 14.2 cm, weight 52.6 ± 12.7 kg, standing reach 219.3 ± 20.8 cm and training experience 5.5 ± 0.1 y); and control group (FLAT, n = 16, age 12.9 ± 0.3 y, height 169.5 ± 9.3 cm, weight 56.2 ± 11.3 kg, standing reach 220.2 ± 15.3 cm and training experience 5.3 ± 0.1y). All participants competed at elite youth level in Under 14 National Basketball Championship. All the participants were healthy, without muscular, neurological and tendinous injuries and did not attend any other physical activity during the training program. All players and their parents were informed about the research procedures, requirements, benefits and risks and their written consent was obtained before the study began. Additionally, players were informed that they were free to withdraw at any time without any penalty. The investigation was approved by the local Institutional Research Ethics Committee and conformed to the recommendations of the Declaration of Helsinki.
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2.2. Design A two-group parallel randomized, pre- to post-test design was used [23]. The training program was employed for both groups during 4 weeks, 3 sessions in a week consisting of 90 minutes per session with three alternating days per week in a total of twelve training sessions and two testing sessions (pre- and post-test). All sessions were performed under similar environment conditions (relative humidity ∼60%) and circumstances (from 11.00 to 12.30 h) on a cushioned porous acrylic sports outdoor surface. All training sessions started with a 20-min standard warmup, with a preliminary articular and muscular mobilization consisting of low-intensity running and a dynamic stretching workout. Following this period, a main workout was performed aiming to increase speed and power of players, including jumps, hops, bounds and basic sprint drills. Both groups performed the following drills: • double jumps maximizing the vertical and horizontal motion component (Foot contacts per workout = 20); • hops maximizing the repeated motion (Foot contact per workout = 30); • alternate-leg bounding exaggerated horizontal movements (Foot contact per workout = 30); • basic sprint drills including walking on toes, walking on heels, sprint arm action, leg cycling and drives, butt kicks and skips (foot contact per workout = 110). Each exercise was performed five times with passive recovery in between, with a work-rest interval ranging from 1:5 to 1:20 targeting an adequate recovery of ATP-PC system [24]. Both groups performed the same exercises during the week microcycle, however, the FLAT performed all training sessions using flat conditions, while the SLOPE used downhill (9◦ degrees), flat and uphill conditions (9◦ degrees) respectively on the first, second and third days of microcycle. The total number of repetitions and work-rest ratio was similar in both groups. The session ended with a 10-min standardized cool-down, which consisted of jogging and stretching exercises. None of the players were familiarized with over-speed training, and the respectively concentric and eccentric contractions.
2.3. Methodology 2.3.1. Anthropometric variables The assessment of anthropometric parameters was carried out twice: one day before the beginning of the protocol (pretest) and two days after the training program’s last session (post-test). Height was measured using a Martin anthropometer (GPM Siber-Hegner, Switzerland) with an accuracy of ±0.1 cm. Weight and fat mass of each participant were assessed using a body composition analyser (TBF-300, Tanita UK Ltd. Philpots Close, UK) with an accuracy of ±0.01 kg. Body mass index (BMI; kg/m2) was calculated from the adjusted height and weight indices for each athlete. Muscle/Fat Index was calculated from the adjusted muscle weight and fat weight indices for each athlete. Standing reach was assessed using a vertical jump-measuring device (Vertec, Gill Athletics, USA).
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xxx.e4 2.3.2. Hand grip The hand grip strength was assessed using a portable digital hand dynamometer (Jamar, EN- 120604) according to the protocol guidelines [25]. The testing protocol consisted of three isometric contractions for 5 seconds, on both hands, with a rest period of at least 60 seconds. The highest recorded value was used for the determination of maximal grip strength [25]. 2.3.3. Jump performance test Lower limb explosive power (W) was assessed using a vertical drop jump (DJ drop height = 0.20 m). Each basketball player performed a DJ test with an Optojump TM device (Microgate, Bolzano, Italy) used to measure the jump height (cm) and contact time (ms) as a proxy for a muscular stretch-shortening performance [26]. During DJ, players were advised to jump as high as possible with minimum contact time, with the hands fixated at the hips. Jumping height was calculated according to the flight time method [27]. 2.3.4. Respiratory volume The pulmonary function test was assessed using a Spirometer Pony FX (Cosmed Ltd., Italy). All players were informed about the instrument set-up and procedures. The protocol test consisted in perform the pulmonary function test for three times and the best of the three results were considered for record. 2.3.5. Margaria-Kalamen anaerobic alactic power test The Margaria-Kalamen stair climb measure the athlete’s lower body peak power [28]. The participants began the test at a starting line placed 5 meters from the first step. One timer was positioned on the 3rd step and a second timer was positioned on the 9th step. On the researcher’s signal, the participant ran from the 5-meter starting mark as fast as he could up the stairway taking the steps three at a time (3rd, 6th, 9th). The timers started recording when the participant hit the 3rd step and stopped recording when the participant stepped on the 9th step. The average time was taken from the two timers for each trial. The participant completed 3 trials with a 20-s rest period prior to the start of each trial and the best performance time was used. The anaerobic power was measured in watts and was the product of force (weight of participant) multiplied by distance (height of stairs) and acceleration due to gravity (9.81 m·sec−1), then divided by time (sec−1). This computation of anaerobic power in watts used the equation [29]: AnaerobicAlacticPower(watts) = (bodymass(kg) × distance(0.96 m) × 9.81m·sec − 1)/time(sec − 1).
2.3.6. Simple reaction test Simple Reaction test belongs to the Vienna Test System (VTS) SPORT (Schuhfried GmbH, Moedling, Austria). The system is composed of a portable computer coupled to a VTS response panel and software. Participants sat at approximately 50 cm from the computer screen, which was positioned about 15 cm in front of the response panel and at the same height. In the middle of the response panel was the black square
B. Figueira et al. button and 5 cm below was the sensor button. To respond to stimuli presented, the participants used the index finger of the preferred hand. The other hand was placed next to the response panel. Before the test the participants were given instructions and allowed time to practice (until they carried out 5 reruns correctly executed). VTS simple RT consisted of a yellow light shown as a visual stimulus that appeared on the screen at random intervals. The participant had to react as quickly as possible by pressing a square black button on the panel. While there was no stimulus shown the participant’s, finger remained on a sensor button. The parameter measured in test was the time lapse (ms) between the appearance of the stimulus on the screen and the finger leaving the sensor and pressing the black button. The errors in choice RT were not assessed due to low incidence (this circumstance happened in less than 1% of the cases and neither of the participants made the mistake more than twice). 2.3.7. Finger-tapping test The finger-tapping test is a neuropsychological test that examines motor function, specifically, motor speed and lateralized coordination. In this study, a single FTT (index finger) was employed. Each participant was seated comfortably in a chair 50 cm from the computer screen, and had a wrist support [30]. The participants were asked to tap a predetermined key on the keyboard repeatedly at the maximum rate possible for 10 s. The single FTT was conducted using a digital Finger Tapping Test system [31]. The system records and saves the tapping data on the hard drive of a computer for later analysis. 2.3.8. Hexagon agility test The Hexagon Agility Test measure the ability to move quickly while maintaining balance [32]. Given the signal, participant jumps forward over the line and returns to the center of the hexagon. Looking in the same direction, they will repeat the action on each side of the hexagon clockwise. The stopwatch will stop when he finishes three complete turns, and his feet are at the center of the hexagon again. The athlete has 5 min rest and then repeats the test. The time that was registered, was the better of his two attempts. A practice trial was allowed prior to recording scores to attenuate the possibility of a learning effect.
2.4. Statistical analysis A descriptive analysis was performed using means and standard deviations. To identify the possibly impair/improve effects of the intervention on players’ performance measures, the data were analysed with a specific spreadsheet for pre-post parallel group trial [33]. The effects were estimated in percent units through log-transformation and uncertainty in the estimate was expressed as 95% confidence limits. Smallest worthwhile differences were estimated from the standardized units multiplied by 0.2 and the probabilities were reported using the following scale: 25—75% possibly; 75—95% likely; 95—99% very likely; > 99% most likely [34]. Standardized (Cohen’s d) mean differences, and respective 90% confidence intervals were also computed as magnitude of observed effects, and, thresholds were 0.2,
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Effects of combined sloped training on basketball players’ Table 1
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Inferences for the FLAT vs. SLOPE intervention on players’ characteristics measures.
Variables
Height (cm) Weight (kg) BMI (kg/m2 ) Dyna R (kg) Dyna L (kg) Resp. vol (L) Musc. mass (kg) Fat mass (kg) Musc/fat index (a.u.) Stand height reach (cm)
Pre
Post
Pre
Post
Differences in means % [90% confidence intervals]
169.47 ± 9.35 56.22 ± 11.26 19.38 ± 2.26 33.27 ± 6.97 32.60 ± 5.80 3.77 ± 0.57 30.19 ± 7.10 6.03 ± 1.60 5.14 ± 1.20
169.77 ± 9.27 56.51 ± 11.23 19.44 ± 2.25 33.93 ± 6.64 31.67 ± 5.68 3.75 ± 0.56 30.21 ± 7.07 5.97 ± 1.65 5.25 ± 1.27
168.83 ± 14.23 52.63 ± 12.71 18.19 ± 1.75 29.73 ± 6.12 28.60 ± 6.16 3.61 ± 0.77 27.29 ± 6.68 5.41 ± 1.52 5.21 ± 1.25
169.10 ± 14.11 53.06 ± 12.97 18.27 ± 1.75 29.87 ± 5.78 29.87 ± 6.81 3.77 ± 0.89 27.65 ± 6.78 5.53 ± 1.50 5.12 ± 1.12
0.0 [−0.2 to 0.2] 0.2 [−0.4 to 0.8] 0.1 [−0.7 to 0.9] −1.6 [−7.1 to 4.2] 7.3 [0.7 to 14.3] 4.9 [0.6 to 9.3] 1.2 [0.4 to 2.1] 4.3 [−0.3 to 9.0] −3.1 [−7.1 to 1.1]
FLAT group
SLOPE group
220.20 ± 15.35 221.07 ± 15.23 219.33 ± 20.81 219.80 ± 20.08 −0.20 [−0.8 to 0.4]
Practical inferences Most like trivial Most like trivial Most like trivial Unclear Likely beneficial Possibly beneficial Most likely trivial Possibly harmful Possibly harmful Most like trivial
Figure 1 Standardized (Cohen) differences between control and experimental groups. Error bars indicate uncertainty in the true mean changes with 90% confidence intervals. BMI: body mass index.
trivial; 0.6, small; 1.2, moderate; 2.0, large; and > 2.0, very large [34].
3. Results Table 1 and Fig. 1 present the practical inferences and standardized Cohen’s d differences based on the pre-post parallel group trial analysis. Results showed different trends between both training methods. Overall, the SLOPE group
presented a small increase in left hand grip strength test (difference in means: % [90% CL], likely beneficial, 7.3% [0.7% to 14.3%] and respiratory volume (possibly beneficial, 4.9% [0.6% to 9.3%]) than FLAT group. Table 2 and Fig. 2 present the practical inferences and standardized Cohen’s d differences to performance variables based on the pre-post parallel group trial analysis. The power results presented an opposite trend between both training methods with the moderate improve results being
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Inferences for the FLAT vs. SLOPE intervention on players’ performance measures.
Stan heigh jump (cm) Drop jump (cm) Contact time (ms) Jump power (W) Jump power (Wkg) Ana Alacti power (W) Ana Alacti power (W/kg) Reaction time (ms) Taping test (s) Hexagon agility (s) 10s Peak (W) Peak (W/kg) Average (W) Average (W/kg)
Pre
Post
Pre
Post
Differences in means % [90% confidence intervals]
48.20 ± 5.29 42.00 ± 7.44 200.20 ± 26.62 1171.20 ± 256.01 20.95 ± 2.90 859.33 ± 160.16 15.36 ± 1.33 179.00 ± 16.49 75.93 ± 6.91 13.21 ± 1.88 699.27 ± 151.29 12.43 ± 1.70 583.67 ± 160.92 10.31 ± 1.88
52.27 ± 4.13 46.00 ± 7.51 192.07 ± 26.95 1331.33 ± 304.19 23.78 ± 4.66 882.00 ± 196.76 15.59 ± 1.312 176.13 ± 12.29 75.27 ± 6.50 11.62 ± 0.77 804.47 ± 236.22 14.11 ± 2.14 589.53 ± 187.10 10.29 ± 1.96
47.20 ± 5.72 42.20 ± 6.17 238.20 ± 35.22 923.07 ± 250.73 17.56 ± 2.61 714.27 ± 195.70 13.50 ± 1.39 182.20 ± 15.27 72.73 ± 6.67 14.37 ± 0.80 612.60 ± 180.29 11.59 ± 1.43 537.73 ± 161.50 10.16 ± 1.34
46.13 ± 6.01 43.53 ± 9.01 216.80 ± 41.85 1011.47 ± 225.18 19.30 ± 3.22 750.80 ± 204.46 14.16 ± 1.37 189.87 ± 15.00 72.40 ± 6.93 13.11 ± 0.74 634.00 ± 197.41 11.88 ± 1.72 554.87 ± 170.71 10.44 ± 1.55
−10.2 [−14.9 to −5.3] −6.8 [−15.8 to 3.2] −5.8 [−14.1 to 3.3] −2.4 [−12.0 to 8.1] −2.7 [−12.4 to 8.0] 3.3 [−1.4 to 8.1] 3.4 [−1.2 to 8.1] 5.8 [1.3 to 10.5] 0.3 [−2.3 to 3.1] 3.0 [−3.0 to 9.4] −9.2 [−15.0 to −3.0] −9.8 [−15.3 to −4.0] 3.0 [−3.6 to 10.1] 2.8 [−3.9 to 9.9]
FLAT group
SLOPE group
Practical inferences
Very likely harmful Unclear Unclear Unclear Unclear Likely trivial Possibly beneficial Likely harmful Unclear Unclear Likely harmful Very likely harmful Unlikely Unclear
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Variables
B. Figueira et al.
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Table 2
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Effects of combined sloped training on basketball players’
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Figure 2 Standardized (Cohen) differences between control and experimental groups. Error bars indicate uncertainty in the true mean changes with 90% confidence intervals.
presented by FLAT group in standing height jump (−10.2% [−14.9% to −5.3%]) and reaction time (5.8% [1.3% to 10.5%]). On the other hand, SLOPE group showed small improve results in anaerobic-alactic power (W/kg) (possibly beneficial, 3.4% [−1.2% to 8.1%]). Athlete’s lower body peak power assessed in cycle ergometer power during 10 seconds, the FLAT group presented small improvements in peak (W), (−9.2% [−15.0% to −3.0%]) and moderate in peak (W/kg) (−9.8% [−15.3% to −4.0%]).
4. Discussion This study aimed to compare the effects of a 4-week combined uphill/downhill/flat training program and a flat training program performed by young non-familiarized basketball players with sloped training. The results of the present study showed that FLAT training group presented moderate improvements in vertical capacity jump and reaction time, as well as in 10 s peak (W) and in peak (W/kg) when compared with SLOPE method.
Uphill running is a popular method to improve running speed performance, requiring an increase in the concentric contraction particularly of the vastus medialis, biceps femoris and gastrocnemius [35,36]. Still, running at a negative gradient (i.e. downhill) primarily requires eccentric contractions, performed by quadriceps muscles [16]. Moreover, several studies identified the effects of a combined uphill-downhill sprint training, showing an increase in maximum running speed (3.5%) and step frequency (3.4%), while flight time (4.3%) and contact time (3.3%) decreased [15]. Other studies quantified the effects of combined uphilldownhill sprint training and showed superior results when compared to a horizontal sprint training [13]. Training program exercises performed under slope conditions promoted a greater exposure to eccentric contraction. It is well known that eccentric actions induce greater muscle damage, mainly because of range of motion and muscle length [37], the type of muscular contraction and the torque generated during exercise [38]. In fact, during eccentric contractions, muscles are stretched and exposed to a
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xxx.e8 greater load than the force developed which may result in muscle micro lesions and acute impairments in performance [39]. On the other hand, high intensity eccentric training is associated with important physiological adaptations in contractile and non-contractile muscle elements [40] which may play an important role in chronic neuromuscular effects such as increased muscle growth and force production [41]. Likewise, the results presented by SLOPE group support to the influence of eccentric contractions performed at higher velocity. The strain placed on a muscle during eccentric contractions depends on the time in which the muscle is under tension and the total number of muscle contractions. Thus, contraction velocity is one of the key variables that affect the torque development and the magnitude of muscle damage [38]. Interestingly, it was already reported that when time under tension is equal, fast velocity during eccentric exercise induces greater muscle damage [42], mainly in untrained subjects as it was the case in this study. It is important to notice that the training program performed in this study aimed to increase speed capacity and power output. Therefore, jumps, hops, bounds and basic sprint drills were performed at high velocities, which mean that eccentric and high-speed actions were combined during training sessions. It is also reported in literature that unaccustomed eccentric exercise may induce greater acute muscle damage, soreness and force impairments [43]. As the players that participated in this study were not familiarized with eccentric training, the probability of increased fatigue due to the mechanical detrimental effects and consequent muscle soreness was high. Despite the identified benefits of uphill/downhill/flat combined stimulus, the results of present study showed a detrimental effect in performance variables in SLOPE compared to FLAT. The post evaluation moment was performed two days after the end of the training program. This means that there was not a progressive reduction of the training load (i.e. taper phase), a common approach used in team sports to reduce the physiological stress of training programs and optimize performance [44]. Literature focused under this scope shows that in the majority of the cases, a supercompensation of physical qualities is observed after a 7—10 days tapering phase such as in muscle torque, vertical jump capacity, sprint capacity [45] and repeated sprint ability [46]. Adding together, the non-familiarization with eccentric exercise and the absence of a taper phase resulted in significant decrements in performance immediately after the cessation of the training program, particularly in standing height jump and reaction time. The FLAT group showed moderate improvements in 10 s peak (W) and in peak (W/kg), SLOPE group also presented improvements, albeit smaller. Available research has shown a tendency to produce shorter concentric phase during downhill training [15]. Thus, this may suggest a more efficient movement pattern through a better propulsive phase and may help to understand our results, supported by an improved ability to produce the same levels of force in a shorter period of time [19]. Overall, the changes presented in left hand grip strength and in respiratory volume (see Table 1 and Fig. 1) are likely beneficial in SLOPE group when compared with FLAT group. However, when considering the pre-post changes, the effect of the 4 weeks seems to be trivial or unclear.
B. Figueira et al. The sample size in this study can be pointed as a limitation due to the training frequency of athletes, which results in problems to find population to apply a training programme with sloped characteristics as well as the duration of 4 weeks. However, present findings should stimulate investigators to examine this topic further.
5. Conclusion The present study showed than despite the identified benefits of combined uphill/downhill/flat training method, young non-familiarize players need a progressive reduction of training load to optimize performance. The results provided evidence that eccentric contractions performed at higher velocity induce greater acute muscle damage, increasing mechanical detrimental effects that significant affect the performance. On the other hand, the maturation status of young players may have affected some physical adaptations as well as the final programme outcomes. These results represent important evidence into the planning guidelines of strength and conditioning coaches to support daily planning by choosing the most appropriate tasks that can enhance players’ performance.
Disclosure of interest The authors declare that they have no competing interest.
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