- Email: [email protected]
Maximal inspiratory mouth pressure in Japanese elite male athletes
Accepted Manuscript Title: Maximal inspiratory mouth pressure in Japanese elite male athletes Author: Toshiyuki Ohya Masahiro Hagiwara Kentaro Chino Yasuhiro Suzuki PII: DOI: Reference:
S1569-9048(16)30074-X http://dx.doi.org/doi:10.1016/j.resp.2016.05.004 RESPNB 2651
To appear in:
Respiratory Physiology & Neurobiology
Received date: Revised date: Accepted date:
24-4-2016 9-5-2016 10-5-2016
Please cite this article as: Ohya, Toshiyuki, Hagiwara, Masahiro, Chino, Kentaro, Suzuki, Yasuhiro, Maximal inspiratory mouth pressure in Japanese elite male athletes.Respiratory Physiology and Neurobiology http://dx.doi.org/10.1016/j.resp.2016.05.004 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Title: Maximal inspiratory mouth pressure in Japanese elite male athletes Authors: Toshiyuki Ohyaa, Masahiro Hagiwaraa, Kentaro Chinoa, and Yasuhiro Suzukia Affiliation: a
Japan Institute of Sports Science, 3-15-1 Nishigaoka, Kita-ku, Tokyo 115-0056, Japan
Corresponding author: Toshiyuki Ohya, Ph.D. Department of Sports Science, Japan Institute of Sports Sciences, Tokyo 115-0056, Japan Tel./Fax: +81-3-5963-0231/+81-3-5963-0232 E-mail: [email protected]
1
Highlights Maximal inspiratory mouth pressure (MIP) characteristics of athletes vary across sport types.
Participants in this study were 301 Japanese elite male athletes.
In absolute terms, the MIP of athletes with higher body mass tended to be stronger.
Athletes who experienced inspiratory muscle fatigue tended to have stronger MIP.
Abstract Maximal inspiratory mouth pressure (MIP) is a common measurement of inspiratory muscle strength, which is often used in a variety of exercises to evaluate the effects of inspiratory muscle training. An understanding of elite athletes’ MIP characteristics is needed to guide sport-specific inspiratory muscle training programs. The purpose of this study was to investigate and better understand the MIP characteristics of elite athletes from a variety of sports. A total of 301 Japanese elite male athletes participated in this study. MIP was assessed using a portable autospirometer with a handheld mouth pressure meter. Athletes with higher body mass tended to have stronger MIP values, in absolute terms. In relative terms, however, athletes who regularly experienced exercise-induced inspiratory muscle fatigue tended to have stronger MIP values. Our 2
findings suggest that athletes could benefit from prescribed, sport-specific, inspiratory muscle training or warm-ups.
Keywords Respiratory muscle, PImax, Pulmonary function, Inspiratory muscle training
Introduction Maximal inspiratory mouth pressure (MIP) is commonly used to measure inspiratory muscle strength; it reflects the combined force-generating capacity of the inspiratory muscles during a brief, quasi-static contraction. Because MIP measurements are taken using volitional, non-invasive techniques, which are better tolerated by participants than balloon catheter systems, the index often uses a variety of exercises to evaluate the effects of inspiratory muscle training or warm-ups (HajGhanbari et al., 2013). Inspiratory muscle training is classified into two major categories: inspiratory muscle strength training and inspiratory muscle endurance training. Inspiratory muscle strength training is performed by breathing against an external inspiratory load. This load is often adjusted with reference to MIP (HajGhanbari et al., 2013). Inspiratory muscle training requires participants to achieve a threshold pressure to open the valve of an inspiratory muscle training device (e.g., the POWERbreathe inspiratory muscle trainer) to provide an inflow of air (HajGhanbari et al., 2013). Substantial respiratory strength is needed to achieve and maintain the target threshold pressure, which ranges 3
between 50% and 80% of MIP (HajGhanbari et al., 2013). Inspiratory muscle warm-up is typically performed at 40% of MIP (Ohya et al., 2015; Volianitis et al., 2001), and has been found to improve inspiratory muscle function (Ohya et al., 2015) and exercise performance (Volianitis et al., 2001). However, the optimal inspiratory muscle training or warm-up loads for athletes, based on their specific sports, remain unclear. The characteristics of MIP have already been reported in both young (Leech et al., 1983), and older adults (Summerhill et al., 2007). To our knowledge, no study has quantified and reported the MIPs of elite athletes across a variety of sports. An understanding of the characteristics of elite athletes’ MIPs is needed to guide inspiratory muscle training programs relative to specific sports. The purpose of this study was to understand the MIP characteristics at rest in a variety of sport-specific elite athletes.
Methods Participants Participants in this study were 301 Japanese elite male athletes and 28 normal healthy males. Table 1 shows the age, height, and body mass of the participants. All the athletes were recruited following medical and/or fitness checks conducted in the Japan Institute of Sports Sciences. Written consent to participate was obtained from all participants after informing them of the purpose of the experiment, the procedure, and the possible risks. This study was approved by the Human Subjects Committee at the Japan Institute of Sports Sciences.
4
MIP measurement MIP was assessed according to published guidelines (American Thoracic Society/European Respiratory Society, 2002), using a portable autospirometer (AS-507; Minato Medical Science, Osaka, Japan) with a handheld mouth pressure meter (AAM377; Minato Medical Science) (Ohya et al., 2016). All measurements were made while the participant sat with their nose occluded. Participants were instructed to breathe out to residual volume and then inhale as hard and as quickly as possible to total lung capacity and sustain this inspiration for at least 1 s. Measurements were repeated until a minimum of five and a maximum of seven technically satisfactory measurements were obtained; the greatest of the three measurements that had less than 10% between-measurement variability was defined as the maximum (McConnell, 2007).
Statistical analysis Values are expressed as means ± standard deviation (SD). Statistical analyses were performed using SPSS for Windows, Version 19.0 (IBM Corp., Armonk, NY, USA). Correlations between the MIP value and height and body mass of each athlete were determined and tested for significance using the Pearson product-moment correlation. Significance was set at P < 0.05.
Results Figure 1 shows the MIP values of Japanese elite male athletes; the mean was 132.8 ± 17.3 cmH2O. Figure 2 shows the athletes’ MIP values relative to their body mass; the 5
mean was 1.85 ± 0.21 cmH2Okg−1. A strong correlation (r = 0.59, P < 0.001) was observed between mean MIP values and mean body mass of athletes from each sport, but no correlation was found between mean MIP values and mean height (r = 0.11, P > 0.05).
Discussion This is the first study to investigate the MIP characteristics of Japanese elite male athletes. In absolute terms, the MIP values of athletes with higher body mass tended to be stronger (Fig. 1). Hautman et al. (Hautmann et al., 2000) reported that MIP was strongly correlated with body mass in healthy males. In another study, body mass was found to affect lung function (Schoenberg et al., 1978); the authors suggested that the improved lung function associated with body mass was attributable to the increased muscle bulk (Schoenberg et al., 1978). Previous studies have reported that inspiratory muscle fatigue (IMF) occurs after swimming (Brown and Kilding, 2011), short-duration high-intensity exercise (Ohya et al., 2016), and long-duration exercise (Ross et al., 2008). In relative terms, athletes whose sport typically demands exercise-induced IMF (e.g., middle-distance runners, triathletes, swimmers and long-distance runners in this study; Fig. 2) tend to have stronger MIP values than other athletes. For example, swimmers are required to precisely coordinate their frequency of breathing and tidal volume with stroke mechanics, which results in a different breathing pattern compared with on-land exercise (Rodríguez, 2000). Coupled with the increased hydrostatic pressure on the 6
chest, and the potential effect of body position on breathing, these factors individually and collectively likely result in an increased load on the respiratory system (Cordain and Stager, 1988). Furthermore, in a previous study of highly trained female middle-distance runners, we demonstrated that IMF occurred after a 400-m and 800-m running test (Ohya et al., 2016). Running requires additional work from the inspiratory muscles; therefore, runners might be more susceptible to IMF than other athletes. Further research is needed to clarify the relationship between the relative MIP values and the exercise modality (e.g., cycling, running, swimming, and rowing) and situation (e.g., on-land and under water). There are two potential limitations of our study. First, all of the athletes were male; the male diaphragm is less fatigue resistant than the female diaphragm (Guenette et al., 2010). Minute ventilation in males progressively and linearly increases with time spent at a fixed work rate, while minute ventilation in females plateaus despite continuing to perform the same muscular task. Therefore, females use a smaller fraction of their maximal exercise ventilatory capacity (Guenette et al., 2010). Further research is needed to confirm the MIP characteristics of elite female athletes from a variety of sports. Another limitation of this study is that the inspiratory muscle strength measurements were volitional. Because the MIP is volitional, holistically measured, and cannot give information about specific muscles, the MIPs recorded may not be truly maximal. Volitional measurements were made because non-invasive techniques have been shown to be better tolerated by participants than the balloon catheter system. Though subject to greater variation than more invasive techniques, non-invasive 7
measurements have been shown to be reliable and valid (Romer and McConnell, 2004; Wijkstra et al., 1995). This study demonstrates that the MIP characteristics of elite male athletes vary across sport types. Inspiratory muscle training can improve sporting performance for some athletes, and clearly increases inspiratory muscle strength (HajGhanbari et al., 2013). The specific type of sport will influence the extent of the benefits derived from inspiratory muscle training. Our findings may benefit coaches who wish to prescribe inspiratory muscle training or warm-ups, according to their athletes’ specific sport.
Conflict of interest The authors declare that there is no conflict of interest related to this study.
Acknowledgements We greatly appreciate Mrs. S. Inada, Miss C. Aikawa, and Miss. Y. Uematsu for their assistance during the study.
8
References American Thoracic Society/European Respiratory Society, 2002. ATS/ERS Statement on respiratory muscle testing. Am J Respir Crit Care Med 166, 518–624. Brown, S., Kilding, A.E., 2011. Exercise-induced inspiratory muscle fatigue during swimming: the effect of race distance. J Strength Cond Res 25, 1204–1209. Cordain, L., Stager, J., 1988. Pulmonary structure and function in swimmers. Sports Med 6, 271–278. Guenette, J.A., Romer, L.M., Querido, J.S., Chua, R., Eves, N.D., Road, J.D., McKenzie, D.C., Sheel, A.W., 2010. Sex differences in exercise-induced diaphragmatic fatigue in endurance-trained athletes. J Appl Physiol 109, 35–46. HajGhanbari, B., Yamabayashi, C., Buna, T.R., Coelho, J.D., Freedman, K.D., Morton, T.A., Palmer, S.A., Toy, M.A., Walsh, C., Sheel, A.W., Reid, W.D., 2013. Effects of respiratory muscle training on performance in athletes: a systematic review with meta-analyses. J Strength Cond Res 27, 1643–1663. Hautmann, H., Hefele, S., Schotten, K., Huber, R.M., 2000. Maximal inspiratory mouth pressures (PIMAX) in healthy subjects-what is the lower limit of normal? Respir Med 94, 689–693. Leech, J.A., Ghezzo, H., Stevens, D., Becklake, M.R., 1983. Respiratory pressures and function in young adults. Am Rev Respir Dis 128, 17–23. McConnell, A., 2007. Lung and respiratory muscle function. In: Winter, E.M., Jones, A.M., Davison, R.C.R., Bromley, P.D., Mercer, T.H., (eds) Sport and exercise physiology testing guidelines, 1st edn. Routledge, London, pp 63–75. 9
Ohya, T., Hagiwara, M., Suzuki, Y., 2015. Inspiratory muscle warm-up has no impact on performance or locomotor muscle oxygenation during high-intensity intermittent sprint cycling exercise. Springerplus 4, 556. Ohya, T., Yamanaka, R., Hagiwara, M., Oriishi, M., Suzuki, Y., 2016. The 400- and 800-m track running induces inspiratory muscle fatigue in trained female middle-distance runners. J Strength Cond Res 30, 1433–1437. Rodríguez, F.A., 2000. Maximal oxygen uptake and cardiorespiratory response to maximal 400-m free swimming, running and cycling tests in competitive swimmers. J Sports Med Phys Fitness 40, 87–95. Romer, L.M., McConnell, A.K., 2004. Inter-test reliability for non-invasive measures of respiratory muscle function in healthy humans. Eur J Appl Physiol 91, 167–176. Ross, E., Middleton, N., Shave, R., George, K., McConnell, A., 2008. Changes in respiratory muscle and lung function following marathon running in man. J Sports Sci 26, 1295–1301. Schoenberg, J.B., Beck, G.J., Bouhuys, A., 1978. Growth and decay of pulmonary function in healthy blacks and whites. Respir Physiol 33, 367–393. Summerhill, E.M., Angov, N., Garber, C., McCool, F.D., 2007. Respiratory muscle strength in the physically active elderly. Lung 185, 315–320. Volianitis, S., McConnell, A.K., Koutedakis, Y., Jones, D.A., 2001. Specific respiratory warm-up improves rowing performance and exertional dyspnea. Med Sci Sports Exerc 33, 1189–1193. Wijkstra, P.J., van der Mark, T.W., Boezen, M., van Altena, R., Postma, D.S., Koëter, 10
G.H., 1995. Peak inspiratory mouth pressure in healthy subjects and in patients with COPD. Chest 107, 652–656.
11
Figure legends Fig. 1 Maximal inspiratory mouth pressure (MIP) values of Japanese elite male athletes. (No.) represents number of participants. The numbers on the right represent the mean values for each sport.
12
Fig. 2 Maximal inspiratory mouth pressure (MIP) values relative to body mass of Japanese elite male athletes. (No.) represents number of participants. The numbers on the right represent the mean values for each sport.
13
Table 1. Characteristics of Japanese elite male athletes and healthy males. alpine skiing
badminton
basketball
canoe
cross-country
cycling (road)
cycling (track)
fencing
freestyle skiing
hockey
(n=5)
(n=19)
(n=14)
(n=9)
skiing (n=9)
(n=11)
(n=12)
(n=8)
(n=5)
(n=19)
age (years)
22.8 ± 2.2
24.8 ± 4.0
22.9 ± 2.0
24.7 ± 2.8
22.8 ± 2.5
20.8 ± 0.9
24.8 ± 4.5
24.3 ± 3.5
24.0 ± 3.1
25.3 ± 3.9
height (cm)
172.8 ± 4.8
174.1 ± 4.4
186.8 ± 10.0
175.5 ± 4.0
173.0 ± 4.4
171.1 ± 5.9
175.7 ± 4.6
176.4 ± 5.1
169.6 ± 6.3
174.5 ± 3.4
body mass (kg)
76.5 ± 5.4
71.6 ± 5.7
86.4 ± 14.5
82.8 ± 6.5
70.4 ± 4.7
60.6 ± 5.3
75.3 ± 6.3
72.0 ± 6.6
68.6 ± 6.8
71.6 ± 6.3
hurdles
jumping
long-distance
middle-distance
nordic combined
rowing
rugby
sailing
short-track speed
snowboarding
(n=13)
(n=10)
running (n=7)
running (n=7)
(n=7)
(n=20)
(n=24)
(n=9)
skating (n=12)
(n=8)
age (years)
23.9 ± 2.7
24.9 ± 2.9
24.1 ± 2.7
24.1 ± 3.2
24.3 ± 4.0
23.6 ± 3.9
27.6 ± 4.3
28.4 ± 4.6
22.5 ± 2.2
24.3 ± 4.2
height (cm)
181.0 ± 4.9
179.0 ± 5.1
169.7 ± 5.6
174.4 ± 3.4
173.9 ± 4.4
178.1 ± 3.6
181.8 ± 8.1
178.2 ± 9.5
170.3 ± 6.1
173.5 ± 4.8
body mass (kg)
71.7 ± 6.7
67.8 ± 6.0
56.2 ± 4.0
63.6 ± 5.0
65.3 ± 6.2
72.3 ± 3.2
101.0 ± 13.1
71.5 ± 9.7
65.1 ± 6.8
71.3 ± 9.5
speed skating
swimming
triathlon
walking
water polo
weight lifting
wrestling
wrestling
wrestling
healthy male
(n=5)
(n=12)
(n=12)
(n=8)
(n=7)
(n=9)
(light) (n=7)
(middle) (n=7)
(heavy) (n=6)
(n=28)
age (years)
26.0 ± 4.6
22.1 ± 2.0
26.5 ± 5.3
26.0 ± 3.9
25.7 ± 1.1
23.4 ± 2.7
22.9 ± 2.7
22.3 ± 3.2
24.0 ± 2.5
24.4 ± 4.2
height (cm)
171.6 ± 4.3
180.2 ± 5.0
172.3 ± 4.1
175.3 ± 6.5
182.7 ± 4.7
169.8 ± 10.1
163.4 ± 3.8
175.3 ± 3.5
178.4 ± 7.0
171.5 ± 5.8
body mass (kg)
71.6 ± 6.0
75.8 ± 7.9
64.7 ± 4.8
60.7 ± 4.5
83.0 ± 9.9
88.5 ± 29.8
63.9 ± 3.8
79.3 ± 5.2
111.8 ± 10.7
64.5 ± 8.7
14
S1569-9048(16)30074-X http://dx.doi.org/doi:10.1016/j.resp.2016.05.004 RESPNB 2651
To appear in:
Respiratory Physiology & Neurobiology
Received date: Revised date: Accepted date:
24-4-2016 9-5-2016 10-5-2016
Please cite this article as: Ohya, Toshiyuki, Hagiwara, Masahiro, Chino, Kentaro, Suzuki, Yasuhiro, Maximal inspiratory mouth pressure in Japanese elite male athletes.Respiratory Physiology and Neurobiology http://dx.doi.org/10.1016/j.resp.2016.05.004 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Title: Maximal inspiratory mouth pressure in Japanese elite male athletes Authors: Toshiyuki Ohyaa, Masahiro Hagiwaraa, Kentaro Chinoa, and Yasuhiro Suzukia Affiliation: a
Japan Institute of Sports Science, 3-15-1 Nishigaoka, Kita-ku, Tokyo 115-0056, Japan
Corresponding author: Toshiyuki Ohya, Ph.D. Department of Sports Science, Japan Institute of Sports Sciences, Tokyo 115-0056, Japan Tel./Fax: +81-3-5963-0231/+81-3-5963-0232 E-mail: [email protected]
1
Highlights Maximal inspiratory mouth pressure (MIP) characteristics of athletes vary across sport types.
Participants in this study were 301 Japanese elite male athletes.
In absolute terms, the MIP of athletes with higher body mass tended to be stronger.
Athletes who experienced inspiratory muscle fatigue tended to have stronger MIP.
Abstract Maximal inspiratory mouth pressure (MIP) is a common measurement of inspiratory muscle strength, which is often used in a variety of exercises to evaluate the effects of inspiratory muscle training. An understanding of elite athletes’ MIP characteristics is needed to guide sport-specific inspiratory muscle training programs. The purpose of this study was to investigate and better understand the MIP characteristics of elite athletes from a variety of sports. A total of 301 Japanese elite male athletes participated in this study. MIP was assessed using a portable autospirometer with a handheld mouth pressure meter. Athletes with higher body mass tended to have stronger MIP values, in absolute terms. In relative terms, however, athletes who regularly experienced exercise-induced inspiratory muscle fatigue tended to have stronger MIP values. Our 2
findings suggest that athletes could benefit from prescribed, sport-specific, inspiratory muscle training or warm-ups.
Keywords Respiratory muscle, PImax, Pulmonary function, Inspiratory muscle training
Introduction Maximal inspiratory mouth pressure (MIP) is commonly used to measure inspiratory muscle strength; it reflects the combined force-generating capacity of the inspiratory muscles during a brief, quasi-static contraction. Because MIP measurements are taken using volitional, non-invasive techniques, which are better tolerated by participants than balloon catheter systems, the index often uses a variety of exercises to evaluate the effects of inspiratory muscle training or warm-ups (HajGhanbari et al., 2013). Inspiratory muscle training is classified into two major categories: inspiratory muscle strength training and inspiratory muscle endurance training. Inspiratory muscle strength training is performed by breathing against an external inspiratory load. This load is often adjusted with reference to MIP (HajGhanbari et al., 2013). Inspiratory muscle training requires participants to achieve a threshold pressure to open the valve of an inspiratory muscle training device (e.g., the POWERbreathe inspiratory muscle trainer) to provide an inflow of air (HajGhanbari et al., 2013). Substantial respiratory strength is needed to achieve and maintain the target threshold pressure, which ranges 3
between 50% and 80% of MIP (HajGhanbari et al., 2013). Inspiratory muscle warm-up is typically performed at 40% of MIP (Ohya et al., 2015; Volianitis et al., 2001), and has been found to improve inspiratory muscle function (Ohya et al., 2015) and exercise performance (Volianitis et al., 2001). However, the optimal inspiratory muscle training or warm-up loads for athletes, based on their specific sports, remain unclear. The characteristics of MIP have already been reported in both young (Leech et al., 1983), and older adults (Summerhill et al., 2007). To our knowledge, no study has quantified and reported the MIPs of elite athletes across a variety of sports. An understanding of the characteristics of elite athletes’ MIPs is needed to guide inspiratory muscle training programs relative to specific sports. The purpose of this study was to understand the MIP characteristics at rest in a variety of sport-specific elite athletes.
Methods Participants Participants in this study were 301 Japanese elite male athletes and 28 normal healthy males. Table 1 shows the age, height, and body mass of the participants. All the athletes were recruited following medical and/or fitness checks conducted in the Japan Institute of Sports Sciences. Written consent to participate was obtained from all participants after informing them of the purpose of the experiment, the procedure, and the possible risks. This study was approved by the Human Subjects Committee at the Japan Institute of Sports Sciences.
4
MIP measurement MIP was assessed according to published guidelines (American Thoracic Society/European Respiratory Society, 2002), using a portable autospirometer (AS-507; Minato Medical Science, Osaka, Japan) with a handheld mouth pressure meter (AAM377; Minato Medical Science) (Ohya et al., 2016). All measurements were made while the participant sat with their nose occluded. Participants were instructed to breathe out to residual volume and then inhale as hard and as quickly as possible to total lung capacity and sustain this inspiration for at least 1 s. Measurements were repeated until a minimum of five and a maximum of seven technically satisfactory measurements were obtained; the greatest of the three measurements that had less than 10% between-measurement variability was defined as the maximum (McConnell, 2007).
Statistical analysis Values are expressed as means ± standard deviation (SD). Statistical analyses were performed using SPSS for Windows, Version 19.0 (IBM Corp., Armonk, NY, USA). Correlations between the MIP value and height and body mass of each athlete were determined and tested for significance using the Pearson product-moment correlation. Significance was set at P < 0.05.
Results Figure 1 shows the MIP values of Japanese elite male athletes; the mean was 132.8 ± 17.3 cmH2O. Figure 2 shows the athletes’ MIP values relative to their body mass; the 5
mean was 1.85 ± 0.21 cmH2Okg−1. A strong correlation (r = 0.59, P < 0.001) was observed between mean MIP values and mean body mass of athletes from each sport, but no correlation was found between mean MIP values and mean height (r = 0.11, P > 0.05).
Discussion This is the first study to investigate the MIP characteristics of Japanese elite male athletes. In absolute terms, the MIP values of athletes with higher body mass tended to be stronger (Fig. 1). Hautman et al. (Hautmann et al., 2000) reported that MIP was strongly correlated with body mass in healthy males. In another study, body mass was found to affect lung function (Schoenberg et al., 1978); the authors suggested that the improved lung function associated with body mass was attributable to the increased muscle bulk (Schoenberg et al., 1978). Previous studies have reported that inspiratory muscle fatigue (IMF) occurs after swimming (Brown and Kilding, 2011), short-duration high-intensity exercise (Ohya et al., 2016), and long-duration exercise (Ross et al., 2008). In relative terms, athletes whose sport typically demands exercise-induced IMF (e.g., middle-distance runners, triathletes, swimmers and long-distance runners in this study; Fig. 2) tend to have stronger MIP values than other athletes. For example, swimmers are required to precisely coordinate their frequency of breathing and tidal volume with stroke mechanics, which results in a different breathing pattern compared with on-land exercise (Rodríguez, 2000). Coupled with the increased hydrostatic pressure on the 6
chest, and the potential effect of body position on breathing, these factors individually and collectively likely result in an increased load on the respiratory system (Cordain and Stager, 1988). Furthermore, in a previous study of highly trained female middle-distance runners, we demonstrated that IMF occurred after a 400-m and 800-m running test (Ohya et al., 2016). Running requires additional work from the inspiratory muscles; therefore, runners might be more susceptible to IMF than other athletes. Further research is needed to clarify the relationship between the relative MIP values and the exercise modality (e.g., cycling, running, swimming, and rowing) and situation (e.g., on-land and under water). There are two potential limitations of our study. First, all of the athletes were male; the male diaphragm is less fatigue resistant than the female diaphragm (Guenette et al., 2010). Minute ventilation in males progressively and linearly increases with time spent at a fixed work rate, while minute ventilation in females plateaus despite continuing to perform the same muscular task. Therefore, females use a smaller fraction of their maximal exercise ventilatory capacity (Guenette et al., 2010). Further research is needed to confirm the MIP characteristics of elite female athletes from a variety of sports. Another limitation of this study is that the inspiratory muscle strength measurements were volitional. Because the MIP is volitional, holistically measured, and cannot give information about specific muscles, the MIPs recorded may not be truly maximal. Volitional measurements were made because non-invasive techniques have been shown to be better tolerated by participants than the balloon catheter system. Though subject to greater variation than more invasive techniques, non-invasive 7
measurements have been shown to be reliable and valid (Romer and McConnell, 2004; Wijkstra et al., 1995). This study demonstrates that the MIP characteristics of elite male athletes vary across sport types. Inspiratory muscle training can improve sporting performance for some athletes, and clearly increases inspiratory muscle strength (HajGhanbari et al., 2013). The specific type of sport will influence the extent of the benefits derived from inspiratory muscle training. Our findings may benefit coaches who wish to prescribe inspiratory muscle training or warm-ups, according to their athletes’ specific sport.
Conflict of interest The authors declare that there is no conflict of interest related to this study.
Acknowledgements We greatly appreciate Mrs. S. Inada, Miss C. Aikawa, and Miss. Y. Uematsu for their assistance during the study.
8
References American Thoracic Society/European Respiratory Society, 2002. ATS/ERS Statement on respiratory muscle testing. Am J Respir Crit Care Med 166, 518–624. Brown, S., Kilding, A.E., 2011. Exercise-induced inspiratory muscle fatigue during swimming: the effect of race distance. J Strength Cond Res 25, 1204–1209. Cordain, L., Stager, J., 1988. Pulmonary structure and function in swimmers. Sports Med 6, 271–278. Guenette, J.A., Romer, L.M., Querido, J.S., Chua, R., Eves, N.D., Road, J.D., McKenzie, D.C., Sheel, A.W., 2010. Sex differences in exercise-induced diaphragmatic fatigue in endurance-trained athletes. J Appl Physiol 109, 35–46. HajGhanbari, B., Yamabayashi, C., Buna, T.R., Coelho, J.D., Freedman, K.D., Morton, T.A., Palmer, S.A., Toy, M.A., Walsh, C., Sheel, A.W., Reid, W.D., 2013. Effects of respiratory muscle training on performance in athletes: a systematic review with meta-analyses. J Strength Cond Res 27, 1643–1663. Hautmann, H., Hefele, S., Schotten, K., Huber, R.M., 2000. Maximal inspiratory mouth pressures (PIMAX) in healthy subjects-what is the lower limit of normal? Respir Med 94, 689–693. Leech, J.A., Ghezzo, H., Stevens, D., Becklake, M.R., 1983. Respiratory pressures and function in young adults. Am Rev Respir Dis 128, 17–23. McConnell, A., 2007. Lung and respiratory muscle function. In: Winter, E.M., Jones, A.M., Davison, R.C.R., Bromley, P.D., Mercer, T.H., (eds) Sport and exercise physiology testing guidelines, 1st edn. Routledge, London, pp 63–75. 9
Ohya, T., Hagiwara, M., Suzuki, Y., 2015. Inspiratory muscle warm-up has no impact on performance or locomotor muscle oxygenation during high-intensity intermittent sprint cycling exercise. Springerplus 4, 556. Ohya, T., Yamanaka, R., Hagiwara, M., Oriishi, M., Suzuki, Y., 2016. The 400- and 800-m track running induces inspiratory muscle fatigue in trained female middle-distance runners. J Strength Cond Res 30, 1433–1437. Rodríguez, F.A., 2000. Maximal oxygen uptake and cardiorespiratory response to maximal 400-m free swimming, running and cycling tests in competitive swimmers. J Sports Med Phys Fitness 40, 87–95. Romer, L.M., McConnell, A.K., 2004. Inter-test reliability for non-invasive measures of respiratory muscle function in healthy humans. Eur J Appl Physiol 91, 167–176. Ross, E., Middleton, N., Shave, R., George, K., McConnell, A., 2008. Changes in respiratory muscle and lung function following marathon running in man. J Sports Sci 26, 1295–1301. Schoenberg, J.B., Beck, G.J., Bouhuys, A., 1978. Growth and decay of pulmonary function in healthy blacks and whites. Respir Physiol 33, 367–393. Summerhill, E.M., Angov, N., Garber, C., McCool, F.D., 2007. Respiratory muscle strength in the physically active elderly. Lung 185, 315–320. Volianitis, S., McConnell, A.K., Koutedakis, Y., Jones, D.A., 2001. Specific respiratory warm-up improves rowing performance and exertional dyspnea. Med Sci Sports Exerc 33, 1189–1193. Wijkstra, P.J., van der Mark, T.W., Boezen, M., van Altena, R., Postma, D.S., Koëter, 10
G.H., 1995. Peak inspiratory mouth pressure in healthy subjects and in patients with COPD. Chest 107, 652–656.
11
Figure legends Fig. 1 Maximal inspiratory mouth pressure (MIP) values of Japanese elite male athletes. (No.) represents number of participants. The numbers on the right represent the mean values for each sport.
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Fig. 2 Maximal inspiratory mouth pressure (MIP) values relative to body mass of Japanese elite male athletes. (No.) represents number of participants. The numbers on the right represent the mean values for each sport.
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Table 1. Characteristics of Japanese elite male athletes and healthy males. alpine skiing
badminton
basketball
canoe
cross-country
cycling (road)
cycling (track)
fencing
freestyle skiing
hockey
(n=5)
(n=19)
(n=14)
(n=9)
skiing (n=9)
(n=11)
(n=12)
(n=8)
(n=5)
(n=19)
age (years)
22.8 ± 2.2
24.8 ± 4.0
22.9 ± 2.0
24.7 ± 2.8
22.8 ± 2.5
20.8 ± 0.9
24.8 ± 4.5
24.3 ± 3.5
24.0 ± 3.1
25.3 ± 3.9
height (cm)
172.8 ± 4.8
174.1 ± 4.4
186.8 ± 10.0
175.5 ± 4.0
173.0 ± 4.4
171.1 ± 5.9
175.7 ± 4.6
176.4 ± 5.1
169.6 ± 6.3
174.5 ± 3.4
body mass (kg)
76.5 ± 5.4
71.6 ± 5.7
86.4 ± 14.5
82.8 ± 6.5
70.4 ± 4.7
60.6 ± 5.3
75.3 ± 6.3
72.0 ± 6.6
68.6 ± 6.8
71.6 ± 6.3
hurdles
jumping
long-distance
middle-distance
nordic combined
rowing
rugby
sailing
short-track speed
snowboarding
(n=13)
(n=10)
running (n=7)
running (n=7)
(n=7)
(n=20)
(n=24)
(n=9)
skating (n=12)
(n=8)
age (years)
23.9 ± 2.7
24.9 ± 2.9
24.1 ± 2.7
24.1 ± 3.2
24.3 ± 4.0
23.6 ± 3.9
27.6 ± 4.3
28.4 ± 4.6
22.5 ± 2.2
24.3 ± 4.2
height (cm)
181.0 ± 4.9
179.0 ± 5.1
169.7 ± 5.6
174.4 ± 3.4
173.9 ± 4.4
178.1 ± 3.6
181.8 ± 8.1
178.2 ± 9.5
170.3 ± 6.1
173.5 ± 4.8
body mass (kg)
71.7 ± 6.7
67.8 ± 6.0
56.2 ± 4.0
63.6 ± 5.0
65.3 ± 6.2
72.3 ± 3.2
101.0 ± 13.1
71.5 ± 9.7
65.1 ± 6.8
71.3 ± 9.5
speed skating
swimming
triathlon
walking
water polo
weight lifting
wrestling
wrestling
wrestling
healthy male
(n=5)
(n=12)
(n=12)
(n=8)
(n=7)
(n=9)
(light) (n=7)
(middle) (n=7)
(heavy) (n=6)
(n=28)
age (years)
26.0 ± 4.6
22.1 ± 2.0
26.5 ± 5.3
26.0 ± 3.9
25.7 ± 1.1
23.4 ± 2.7
22.9 ± 2.7
22.3 ± 3.2
24.0 ± 2.5
24.4 ± 4.2
height (cm)
171.6 ± 4.3
180.2 ± 5.0
172.3 ± 4.1
175.3 ± 6.5
182.7 ± 4.7
169.8 ± 10.1
163.4 ± 3.8
175.3 ± 3.5
178.4 ± 7.0
171.5 ± 5.8
body mass (kg)
71.6 ± 6.0
75.8 ± 7.9
64.7 ± 4.8
60.7 ± 4.5
83.0 ± 9.9
88.5 ± 29.8
63.9 ± 3.8
79.3 ± 5.2
111.8 ± 10.7
64.5 ± 8.7
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