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Results: The segment contribution towards the velocity of the bowling ball at release was described cumulatively as 37.4% from the lower body, 1.6% from the trunk, 46.8% from upper and lower arm, and 13.9% from the hand and fingers. There were no significant differences in terms of percentage of individual segment contributions between male and female bowlers. Qualitative assessment of segment linear velocity–time graphs showed a pattern of sequentiallity, with the peak of the more distal segment occurring following the deceleration of the preceding proximal segment. Discussion: It was summarised that a the majority of the final linear ball velocity in ten pin bowling stemmed from contributions of the walk during approach (37.4%) and the upper limbs (61.7%). However, unlike the findings of trunk contributions in the underarm and overarm throwing patterns of other sports, the trunk contribution in this study was negligible. It is possible that this difference was because bowling involves the use of an extremely heavy ball and the underarm pattern allows a preparatory phase for the ball to be lifted at heights and being allowed to freefall akin to a pendulum. From the potential-kinetic energy relationship and utilising the means of the elite bowlers, it was found that nearly the entire 61.7% upper limb contribution was attributed to gravity as opposed to being muscle driven.
Helsinki for medical research involving human subjects. A motion analysis system (Frame-DIAS4, DKH, Japan) was used to digitize ten body landmarks. Results and discussion: The swimming speed of the subjects showed that the highest speed was maintained during the gliding movement when the knee and the hip joint angles of 180◦ were maintained from the push-off the wall to 0.8 s. On the other hand, the lower limb joints of the non-elite swimmer did not become straight. The main aim of this study was to analyse the gliding and dolphin kick movement in competitive swimmer and investigate whether the streamline of body could maintain the knee and the hip joint angles of 180◦ . During these phases, reducing underwater resistance force leads to the improvement of the swimming performance. The swimmer who maintained a superior streamline maintained the high velocity in the phase that the dolphin kick was performed.
http://dx.doi.org/10.1016/j.jsams.2013.10.173
L. Morrison ∗ , R. Hinman, F. Dobson, P. Nicolson, T. Wrigley, K. Bennell
35 Biomechanical analysis of the gliding and dolphin kick movement in competitive swimmers T. Wada 1,∗ , N. Yamamoto 2 , H. Jigami 3 , Y. Shimoyama 4 , M. Wada 1 , T. Matsumoto 1 1
Kokushikan University, Japan Japanese Red Cross Hokkaido College of Nursing, Japan 3 Tokyo University of Technology, Japan 4 Niigata University of Health and Welfare, Japan 2
Introduction: The improvement of swimming performance is related not only to the effect of stroking but also dolphin kick movement after the start and the turn phase. The dolphin kick movement after the start and turn phases are important for the total race time in modern swimming. We hypothesized that acceleration by dolphin kick movement would assist to increase the swim speeds, consequently, swimmers need to keep a better body position and higher speed after optimal dolphin kick movement. The purpose of this study was to biomechanical analysis of the gliding and dolphin kick movement in competitive swimmers. Methods: Six healthy male collegiate swimmers (age 19.7 ± 1.1yrs, height 174.2 ± 5.2 cm, body weight 68.3 ± 3.6 kg, BMI 22.9 ± 1.8) volunteered to participate in this study. The subjects performed underwater gliding movement as fast as possible after the start wall kicking. During the underwater phase of gliding movement, the swimmers were to hold the streamlined position. In addition, dolphin kick movement performed by maximum effort. The subjects were monitored with an underwater video camera (SK-2130, SONY, Japan) with a sampling frequency of 60 Hz in the sagittal plane to measure the angular displacement of their different joints. The wireless electromyography system (Biolog DL-5000, S&ME, Japan) was used to collect the muscle activities. All subjects received a written and verbal explanation of the study and gave their written informed consent for participation. Approval was granted from the institutional human ethics committee and the study was conducted in conformity with the Declaration of
http://dx.doi.org/10.1016/j.jsams.2013.10.174 36 Biomechanical and neuromuscular impairments in FAI patients: A systematic review
Centre for Health, Exercise and Sports Medicine, The University of Melbourne, Australia Introduction: Femoroacetabular impingement (FAI) is a common condition that can cause hip and/or groin pain in young active adults, plus give rise to stiffness, muscle weakness, reduced physical function and lower quality of life. It has also been proposed as a risk factor for early onset of hip osteoarthritis. Understanding the musculoskeletal impairments associated with FAI is critical in improving conservative management strategies. The purpose of the present study was to systematically review the literature to establish whether people with FAI demonstrate impairments and/or activity limitations compared to people without FAI. Methods: Three electronic databases (Pubmed, CINAHL and SportDISCUS) were searched until the end of January 2013. Studies were included if: the population had symptomatic FAI diagnosed by clinical and imaging features; the comparison was either healthy controls, the asymptomatic contralateral limb of participants with symptomatic FAI, or the study group post-intervention; and the reported outcomes included a measure of impairment and/or activity limitation. Methodological quality was assessed by two raters using the Newcastle-Ottawa Scale. Results: Eleven studies of moderate to high methodological quality fulfilled the eligibility criteria. Sample sizes varied between 10 and 37 participants. Seven studies were cross sectional with five of these including a comparison group of age and gender-matched controls and two using the contralateral hip in patients following total hip replacement. The remaining four studies used a pre/post design comparing the same group post-operative or post treatment. Follow up varied between 8 and 32 months. Outcome measures included biomechanical and neuromuscular factors assessed during various activities. Five studies evaluated hip range of motion (ROM) – two via computed tomography, three examined gait and two evaluated squatting – both via 3-D motion analysis, and one calculated maximum strength of the rectus femoris and tensor fasciae latae. Decreased frontal plane range of motion (adduction/abduction) at the hip was reported during the gait cycle. Other outcomes included a significant decrease in hip ROM in positions
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targeting impingement (flexion/internal rotation), and decreased strength in the hip adductor and flexor muscles. Discussion: Results reported were inconsistent and limited due to the paucity of studies in this area. The scarcity of other outcome measures suggests that further research is needed to better characterise the range of impairments in individuals with FAI. Understanding these potential deficiencies will assist in the development of novel conservative management programs, such as targeted muscle rehabilitation, in order to better manage the condition. http://dx.doi.org/10.1016/j.jsams.2013.10.175 37 The biomechanical effects of cutting decision-making on the lower extremity during a drop-landing T. Owens 1 , A. Shim 1,∗ , J. Beebe 2 , J. Yom 1 1
Division of Kinesiology and Sport Science, The University of South Dakota, United States 2 Department of Physical Therapy, The University of South Dakota, United States Introduction: Female athletes’ anterior cruciate ligament (ACL) injury rates are two to eight times higher than male. Investigations into non-contact ACL injuries suggest that many ruptures occur during a landing or side-cutting motion. The act of decision-making is often present in most athletic competition. This decision making process during landing may alter the biomechanical procedures of the lower extremity which can possibly increase the risk of ACL injury. The purpose of this study was to determine the biomechanical effects of cutting decision-making in a female athletic during a drop landing. Methods: Fourteen collegiate female recreational athletes (age: 21.4 years, range 19–24; height = 170 ± 4.1 cm, mass = 64.9 ± 5.4 kg) performed a drop landing (ht = 0.5 m) with an anticipated right and left directional cuts (ADC). Next, the participants performed trials of unanticipated directional cut (UDC) in both directions as generated by random order. Three trials of all conditions were collected and the biomechanics of the dominant side were examined during cuts to the left. The lower body biomechanics of the dominant side were examined and compared between ADC and UDC. Three dimensional biomechanics data were recorded with 6 Vicon cameras (240 Hz) and two AMTI force plates (960 Hz). We compared UDC–ADC differences scores (p < 0.05) for lower-extremity joint kinematics and ground reaction forces (GRFs) using one sample t-tests. Confidence intervals (CI) at 95% level also were generated. Results: Less maximum knee flexion angle (4.42 ± 7.59) and displacement (4.51 ± 6.0) were exhibited by UDC, compared with ADC. Furthermore, at initial contact (IC), less hip and knee abduction angles (2.34 ± 2.84, and 1.03 ± 1.22, respectively) were exhibited during UDC. However, we found no significant difference in GRF. Discussion: The unanticipated directional cut restricted knee maximum flexion and displacement. Furthermore, the frontal lower extremity alignments were restricted at IC. Consequently, the more extended knee and hip landing position may associate with ACL injury risk. However, the GRFs showed non-significant differences among the variables (Peak vertical GRF, time to peak vertical GRF, and medical GRF). Conclusions: The kinematic changes displayed during UDC may cause an increase in stress on the knee joint. However, the examined GRFs data does not show any significant difference between
conditions. We see that a reactive decision making process may put the ACL at greater risk based on our kinematic results. http://dx.doi.org/10.1016/j.jsams.2013.10.176 38 The Drugs in Sport Project: A comprehensive educational approach F. Boys ∗ , D. Bow Sports Medicine Australia (WA Branch), Australia Drug use is not a new thing in sport, be it for enhancing performance or in social settings outside the competitive environment. While the use of performance enhancing drugs was previously considered the domain of elite sport it is now an issue across all levels of sport including junior competition. Similarly the use of illicit and social drugs has digressed from its amateur sport boundaries and is now problematic at elite level. Sports Medicine Australia (WA Branch) and the Department of Sport and Recreation of Western Australia have developed the Drugs in Sport Project. The principle aim of the Drugs in Sport Project is to raise awareness, provide information and address drugs in sport issues for the active community in Western Australia. The project provides education to the general sporting community including education institutions, club athletes and support personnel through to the elite sporting community at both State and National levels. The Drugs in Sport Project incorporates a comprehensive approach and addresses all categories of drug use from legal social drugs (particularly alcohol) through to the illicit and performance enhancing drugs. Sports Medicine Australia (WA Branch) has a close working relationship with the Australian Sports Anti–Doping Association (ASADA) and uses ASADA information to implement the antidoping education component of the Drugs in Sport Project. The project utilises a range of strategies including face to face presentations to both the elite and community level sporting groups, development of educational resources and the formation of the Be Drug Free website. Other strategies include e-newsletters, development of an online education module and specialised school workshops mapped to current Health & Physical Education K-10 drug education curriculum. The project also aims to facilitate the implementation of appropriate drugs in sport policies at all levels of sport. http://dx.doi.org/10.1016/j.jsams.2013.10.177 39 The effects of a physical warm-up on cognitive performance N. Elsworthy 1,∗ , B. Dascombe 1,2 , D. Burke 3 1 Applied Sports Science and Exercise Testing Laboratory, University of Newcastle, Australia 2 Priority Research Centre in Physical Activity and Nutrition, University of Newcastle, Australia 3 School of Psychology, University of Newcastle, Australia
Introduction: The relationship between cognitive performance and exercise intensity has previously been shown to follow an inverted-U trend. Previous research has highlighted the relationship between cognitive performance and exercise, however no studies have examined the benefits of a physical warm-up on cognitive function. The purpose of this research was to compare cognitive