The Association between Anthropometric Variables, Functional Movement Screen Scores and 100 m Freestyle Swimming Performance in Youth Swimmers
Daisy Bond, Laura Goodson, Samuel W. Oxford, Alan M. Nevill and Michael J. Duncan
Pages 1–11
Abstract: This study examined the association between anthropometric variables, Functional Movement Screen (FMS) scores and 100 m freestyle swimming performance in early adolescent swimmers. Fifty competitive, national level, youth swimmers (21 males, 29 females, mean age ± SD = 13.5 ± 1.5 years, age range 11–16 years) performed an “all-out” 100 m freestyle (front crawl) swim as fast as they could in a 50 m pool. A median divide for 100 m timed swim was also used to divide the sample into faster or slower groups. Height, body mass, skinfolds and limb lengths were also assessed. Maturation was calculated by proxy using anthropometric measures and participants also undertook the FMS as a measure of functional performance. Backwards linear regression indicated a significant model (p = 0.0001, Adjusted R2 = 0.638) explaining 63.8% of the variance in swim performance with total sum of skinfolds, upper leg length, lower leg length, hand length and total height significantly contributing to the model. Swimmers who were classed as fast had lower total sum of skinfolds (p = 0.005) and higher total FMS score (p = 0.005) compared to their slower peers. In summary, this study indicates that anthropometric variables significantly explained the variance in 100 m freestyle swimming performance in youth swimmers.
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Effect of Level and Downhill Running on Breathing Efficiency
Matthew D. Cook, Stephen D. Myers, John S. M. Kelly and Mark E. T. Willems
Pages. 12–20
Abstract: Ventilatory equivalents for oxygen and carbon dioxide are physiological measures of breathing efficiency, and are known to be affected by the intensity and mode of exercise. We examined the effect of level running (gradient 0%) and muscle-damaging downhill running (−12%), matched for oxygen uptake, on the ventilatory equivalents for oxygen () and carbon dioxide (). Nine men (27 ± 9 years, 179 ± 7 cm, 75 ± 12 kg, : 52.0 ± 7.7 mL·kg−1·min−1) completed two 40-min running bouts (5 × 8-min with 2-min inter-bout rest), one level and one downhill. Running intensity was matched at 60% of maximal metabolic equivalent. Maximal isometric force of m.quadriceps femoris was measured before and after the running bouts. Data was analyzed with 2-way ANOVA or paired samples t-tests. Running speed (downhill: 13.5 ± 3.2, level: 9.6 ± 2.2 km·h−1) and isometric force deficits (downhill: 17.2 ± 7.6%, level: 2.0 ± 6.9%) were higher for downhill running. Running bouts for level and downhill gradients had , heart rates and respiratory exchange ratio values that were not different indicating matched intensity and metabolic demands. During downhill running, the , (downhill: 29.7 ± 3.3, level: 27.2 ± 1.6) and (downhill: 33.3 ± 2.7, level: 30.4 ± 1.9) were 7.1% and 8.3% higher (p < 0.05) than level running. In conclusion, breathing efficiency appears lower during downhill running (i.e., muscle-damaging exercise) compared to level running at a similar moderate intensity.
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Epidemiological Review of Injuries in Rugby Union
Jean-François Kaux, Marc Julia, François Delvaux, Jean-Louis Croisier, Bénédicte Forthomme, Damien Monnot, Marie Chupin, Jean-Michel Crielaard, Caroline Le Goff, Patrick Durez, Philippe Ernst, Sébastien Guns and Arnaud Laly
Pages 21–29
Abstract: Rugby is a sport that is growing in popularity. A contact sport par excellence, it causes a significant number of injuries. In Rugby Union, there are 30 to 91 injuries per 1000 match hours. This epidemiological review of injuries incurred by rugby players mentions the position and type of injuries, the causes, time during the match and season in which they occur and the players’ positions as well as the length of players’ absences following the injury.
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The Progression of Male 100 m Sprinting with a Lower-Limb Amputation 1976–2012
Bryce Dyer
Pages 30–39
Abstract: Sprinting with a lower-limb amputation over 100 m has taken place in the Paralympic Games for over three decades. The aim of this paper is to statistically evaluate the performances and participation levels of such athletes during this period. The level of performance improvement over a 36-year period was proposed to be significantly greater than the able-bodied equivalent. Coupled with this, a major spike in amputee running performance improvement was shown to occur from 1984–1988. This supports previously recorded accounts of a major technological change being made at this time. Finally, whilst the average performance of the medallists has increased consistently over the 36-year history, the overall participation in the event fell significantly after 1988 and did not recover until 2012.
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Pitch Sequence Complexity and Long-Term Pitcher Performance
Joel R. Bock
Pages 40–55
Abstract: Winning one or two games during a Major League Baseball (MLB) season is often the difference between a team advancing to post-season play, or “waiting until next year”. Technology advances have made it feasible to augment historical data with in-game contextual data to provide managers immediate insights regarding an opponent’s next move, thereby providing a competitive edge. We developed statistical models of pitcher behavior using pitch sequences thrown during three recent MLB seasons (2011–2013). The purpose of these models was to predict the next pitch type, for each pitcher, based on data available at the immediate moment, in each at-bat. Independent models were developed for each player’s most frequent four pitches. The overall predictability of next pitch type is 74:5%. Additional analyses on pitcher predictability within specific game situations are discussed. Finally, using linear regression analysis, we show that an index of pitch sequence predictability may be used to project player performance in terms of Earned Run Average (ERA) and Fielding Independent Pitching (FIP) over a longer term. On a restricted range of the independent variable, reducing complexity in selection of pitches is correlated with higher values of both FIP and ERA for the players represented in the sample. Both models were significant at the α = 0.05 level (ERA: p = 0.022; FIP: p = 0.0114). With further development, such models may reduce risk faced by management in evaluation of potential trades, or to scouts assessing unproven emerging talent. Pitchers themselves might benefit from awareness of their individual statistical tendencies, and adapt their behavior on the mound accordingly. To our knowledge, the predictive model relating pitch-wise complexity and long-term performance appears to be novel.
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Neuromuscular Retraining in Female Adolescent Athletes: Effect on Athletic Performance Indices and Noncontact Anterior Cruciate Ligament Injury Rates
Frank R. Noyes and Sue D. Barber-Westin
Pages 56–76
Abstract: While many anterior cruciate ligament (ACL) prevention programs have been published, few have achieved significant reductions in injury rates and improvements in athletic performance indices; both of which may increase compliance and motivation of athletes to participate. A supervised neuromuscular retraining program (18 sessions) was developed, aimed at achieving both of these objectives. The changes in neuromuscular indices were measured after training in 1000 female athletes aged 13–18 years, and the noncontact ACL injury rate in 700 of these trained athletes was compared with that of 1120 control athletes. There were significant improvements in the drop-jump test, (p < 0.0001, effect size [ES] 0.97), the single-leg triple crossover hop (p < 0.0001, ES 0.47), the t-test (p < 0.0001, ES 0.64), the multi-stage fitness test (p < 0.0001, ES 0.57), hamstring strength (p < 0.0001), and quadriceps strength (p < 0.01). The trained athletes had a significant reduction in the noncontact ACL injury incidence rate compared with the controls (1 ACL injury in 36,724 athlete-exposures [0.03] and 13 ACL injuries in 61,244 exposures [0.21], respectively, p = 0.03). The neuromuscular retraining program was effective in reducing noncontact ACL injury rate and improving athletic performance indicators.
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A Retrospective Review from 2006 to 2011 of Lower Extremity Injuries in Badminton in New Zealand
Joanna Reeves, Patria A. Hume, Simon Gianotti, Barry Wilson and Erika Ikeda
Pages 77–86
Abstract: Aim: To describe lower extremity injuries for badminton in New Zealand. Methods: Lower limb badminton injuries that resulted in claims accepted by the national insurance company Accident Compensation Corporation (ACC) in New Zealand between 2006 and 2011 were reviewed. Results: The estimated national injury incidence for badminton injuries in New Zealand from 2006 to 2011 was 0.66%. There were 1909 lower limb badminton injury claims which cost NZ$2,014,337 (NZ$ value over 2006 to 2011). The age-bands frequently injured were 10–19 (22%), 40–49 (22%), 30–39 (14%) and 50–59 (13%) years. Sixty five percent of lower limb injuries were knee ligament sprains/tears. Males sustained more cruciate ligament sprains than females (75 vs. 39). Movements involving turning, changing direction, shifting weight, pivoting or twisting were responsible for 34% of lower extremity injuries. Conclusion: The knee was most frequently injured which could be due to multi-planar loading. Turning or cutting movements typically involve motion in the frontal and transverse planes that may place the knee at greater risk of injury than movement in the sagittal plane alone. Further research on badminton specific movements is warranted to better understand the mechanisms of lower extremity injuries in the sport. Sports medicine and support personnel should take into account the susceptibility of the knee to injury when designing training and injury prevention programmes given the large number of change of direction movements during badminton.
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Relationship between the Pedaling Biomechanics and Strain of Bicycle Frame during Submaximal Tests
Aneliya V. Manolova, Samuel Crequy, Philippe Lestriez, Pierre Debraux and William M. Bertucci
Pages 87–102
Abstract: The aim of this study was to analyse the effect of forces applied to pedals and cranks on the strain imposed to an instrumented bicycle motocross (BMX) frame. Using results from a finite element analysis to determine the localisation of highest stress, eight strain gauges were located on the down tube, the seat tube and the right chain stay. Before the pedaling tests, static loads were applied to the frame during bench tests. Two pedaling conditions have been analysed. In the first, the rider was in static standing position on the pedals and applied maximal muscular isometric force to the right pedal. The second pedaling condition corresponds to three pedaling sprint tests at submaximal intensities at 150, 300 and 550 W on a cycle-trainer. The results showed that smaller strain was observed in the pedaling condition than in the rider static standing position condition. The highest strains were located in the seat tube and the right chain stay near the bottom bracket area. The maximum stress observed through all conditions was 41 MPa on the right chain stay. This stress was 11 times lower than the yield stress of the frame material (460 MPa). This protocol could help to adapt the frame design to the riders as a function of their force and mechanical power output. These results could also help design BMX frames for specific populations (females) and rider morphology.
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An Overview of the Running Performance of Athletes with Lower-Limb Amputation at the Paralympic Games 2004–2012
Hossein Hassani, Mansi Ghodsi, Mehran Shadi, Siamak Noroozi and Bryce Dyer
Pages 103-115
Abstract: This paper analyses the performances of lower-limb amputees in the 100, 200 and 400 m running events from the 2004, 2008 and 2012 Paralympic Games. In this paper, four hypotheses are pursued. In the first, it investigates whether the running performance of lower-limb amputees over three consecutive Paralympic Games has changed. In the second, it asks whether a bi-lateral amputee has a competitive advantage over a uni-lateral amputee. In the third, the effect of blade classification has been considered and we attempt to see whether amputees in various classifications have different level of performance. Finally, it is considered whether the final round of competition obtains different levels of performance in comparison to the qualification heats. Based on the outcomes of these investigations, it is proposed that future amputee-based running events should be undertaken with separate and not combined events for the T42, T43 and T44 classifications at the Paralympic Games.
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The Somnolent Youth-Sleep and the Influence of Exercise: A Narrative Review
Haresh T. Suppiah and Michael Chia
Pages 116–135
Abstract: Sleep is crucial to the physiological and psychological development of youth. The implications of insufficient sleep on learning and school performance are well documented. However, adequate sleep often goes unmet due to a combination of biological, societal, and environmental factors, especially during adolescence. In the present review, the changes to adolescent sleep patterns, and its consequences on cognition and learning are briefly explored. We then review the empirical literature of the role of exercise in regulating adolescent sleep patterns, and its potential mechanisms.
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The Effect of High Intensity Intermittent Exercise on Power Output for the Upper Body
Leonie Harvey, Matthew Bousson, Chris McLellan and Dale I. Lovell
Pages 136–144
Abstract: The aim of the present study was to examine and measure high intensity, intermittent upper body performance, in addition to identifying areas of the body that affect the variance in total work done during the 5 × 6 s sprint test. Fifteen males completed an upper body 5 × 6 s sprint test on a modified electro-magnetically braked cycle ergometer, which consisted of five maximal effort sprints, each 6 s in duration, separated by 24 s of passive recovery. A fly wheel braking force corresponding to 5% of the participants’ body weight was used as the implemented resistance level. Body composition was measured using dual-energy X-ray absorptiometry (DEXA). Percent (%) decrement was calculated as 100 − (Total work/ideal work) × 100. Significant (P < 0.05) differences were found between sprints for both absolute and relative (W, W·kg−1, W·kg−1 Lean body mass (LBM) and W·kg−1 Upper body lean body mass (UBLBM)) peak (PP) and mean (MP) power. The % decrement in total work done over the five sprints was 11.4%. Stepwise multiple linear regression analysis revealed that UBLBM accounts for 87% of the variance in total work done during the upper body 5 × 6 s sprint test. These results provide a descriptive analysis of upper body, high intensity intermittent exercise, demonstrating that PP and MP output decreased significantly during the upper body 5 × 6 s sprint test.
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Physical Activity and Gastrointestinal Cancers: Primary and Tertiary Preventive Effects and Possible Biological Mechanisms
Karen Steindorf, Dorothea Clauss, Joachim Wiskemann and Martina E. Schmidt
Pages 145–158
Abstract: Gastrointestinal cancers account for 37% of all cancer deaths worldwide, underlining the need to further investigate modifiable factors for gastrointestinal cancer risk and prognosis. This review summarizes the corresponding evidence for physical activity (PA), including, briefly, possible biological mechanisms. Despite high public health relevance, there is still a scarcity of studies, especially for tertiary prevention. Besides the convincing evidence of beneficial effects of PA on colon cancer risk, clear risk reduction for gastroesophageal cancer was identified, as well as weak indications for pancreatic cancer. Inverse associations were observed for liver cancer, yet based on few studies. Only for rectal cancer, PA appeared to be not associated with cancer risk. With regard to cancer-specific mortality of the general population, published data were rare but indicated suggestive evidence of protective effects for colon and liver cancer, and to a lesser extent for rectal and gastroesophageal cancer. Studies in cancer patients on cancer-specific and total mortality were published for colorectal cancer only, providing good evidence of inverse associations with post-diagnosis PA. Overall, evidence of associations of PA with gastrointestinal cancer risk and progression is promising but still limited. However, the already available knowledge further underlines the importance of PA to combat cancer.
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Narratives of Psychosocial Response to Microtrauma Injury among Long-Distance Runners
Hayley C. Russell and Diane M. Wiese-Bjornstal
Pages 156–177
Abstract: Athletes with microtrauma or overuse injuries resulting from an accumulation of repeated small forces may differ from athletes with macrotrauma or acute injuries in their psychosocial responses because of the unique challenges presented by these insidious-onset and often chronic injuries. Our purpose was to use narrative inquiry to examine the psychosocial experiences and responses of 10 long-distance runners who had experienced microtrauma injuries. Qualitative data analysis of interview data led to a chronological timeline of the injury experience and an assessment of the meaning attributed to these injury experiences using a variation of Mishler’s core-narrative approach. Participants reported distinct thoughts, feelings, and behaviors during each phase of the injury—pre-injury, injury onset, and outcome. In the pre-injury period, participants indicated specific running-related goals and attributed their injuries to overtraining or a change in training. During the injury onset phase, participants consistently indicated two themes: self-diagnosis and treatment, and not taking time off. Within the outcome phase of injury, participants acknowledged changed training because of the injury, and lessons learned from their injury experiences. The narratives of microtrauma-injured runners revealed psychosocial distress and behavioral tendencies post-injury that have important implications for runners, coaches, and healthcare professionals.
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A Comparison of Upper Body Strength between Rock Climbing and Resistance Trained Men
Kristina M. Macias, Lee E. Brown, Jared W. Coburn and David D. Chen
Pages 178–187
Abstract: Studies have shown that advanced rock climbers have greater upper body strength than that of novice climbers or non-climbers. The purpose of this study was to compare upper body strength between rock climbing and resistance trained men. Fifteen resistance trained men (age 25.28 ± 2.26 yrs; height 177.45 ± 4.08 cm; mass 85.17 ± 10.23 kg; body fat 10.13 ± 5.40%) and 15 rock climbing men (age 23.25 ± 2.23 yrs; height 175.57 ± 8.03 cm; mass 66.66 ± 9.40 kg; body fat 6.86 ± 3.82%) volunteered to participate. Rock climbing (RC) men had been climbing for at least two years, 2–3 times a week, able to climb at least a boulder rating of V4–5 and had no current injuries. Resistance trained (RT) men had been total body strength training for at least two years, 2–3 times a week with no current injuries. Each participant performed pull-ups to failure, grip strength, and pinch strength. RT were significantly older and heavier than RC. RC performed significantly more pull-ups (19.31 ± 4.31) than RT (15.64 ± 4.82). RC had greater relative pinch strength (R 0.27 ± 0.10 kg/kg; L 0.24 ± 0.07 kg/kg) than RT (R 0.19 ± 0.04 kg/kg; L 0.16 ± 0.05 kg/kg) and greater relative grip strength (R 0.70 ± 0.10 kg/kg; L 0.65 ± 0.12 kg/kg) than RT (R 0.57 ± 0.14 kg/kg; L 0.56 ± 0.15 kg/kg). Overall, RC men demonstrated greater performance in tests involving relative strength when compared to RT men. Rock climbing can promote increased upper body strength even in the absence of traditional resistance training.
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Upper Extremity Muscle Activation during Bodyblade Exercises Following Six Weeks of Intervention Focusing on the Lumbopelvic-Hip Complex
Gretchen D. Oliver, Audrey J. Stone, Wendi H. Weimar, Lawrence Lemak, Jessica K. Washington and Christopher P. Dougherty
Pages 188–201
Abstract: The current study examined the effects of a six-week lumbopelvic-hip complex (LPHC) strengthening program on muscle activation when performing the shoulder dump exercise. The shoulder dump is a total body exercise that includes overhead arm movements. A pre-post test with a control group was implemented. Twenty-seven graduate students (23.5 ± 1.34 yr; 174.4 ± 11.0 cm; 76.6 ± 16.9 kg) participated. Participants were randomly assigned to a control or intervention group where the intervention group performed LPHC exercises. Two-way analysis of variance (ANOVA) revealed a significant increase in muscle activation of the serratus anterior from pre- and post-LPHC intervention, (t = 6.5, p < 0.001). As presented by these data, incorporation of LPHC exercises may assist in facilitating greater activation in some of the scapula-stabilizing musculature that has traditionally been rehabilitated in prone or side-lying positions. It is, therefore, suggested that LPHC exercises be incorporated in a regular shoulder rehabilitation program.
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The Effect of Kettlebell Swing Load and Cadence on Physiological, Perceptual and Mechanical Variables
Michael J. Duncan, Rosanna Gibbard, Leanne M. Raymond and Peter Mundy
Pages 202–208
Abstract: This study compared the physiological, perceptual and mechanical responses to kettlebell swings at different loads and swing speeds. Following familiarization 16 strength trained participants (10 males, six females, mean age ± SD = 23 ± 2.9) performed four trials: 2 min kettlebell swings with an 8 kg kettlebell at a fast cadence; 2 min kettlebell swings with an 8 kg kettlebell at a slow cadence; 4 min kettlebell swings with a 4 kg kettlebell at a fast cadence; 4 min kettlebell swings with a 4 kg kettlebell at a slow cadence. Repeated measured analysis of variance indicated no significant differences in peak blood lactate or peak net vertical force across loads and cadences (P > 0.05). Significant main effect for time for heart rate indicated that heart rate was higher at the end of each bout than at mid-point (P = 0.001). A significant Load X cadence interaction for rating of perceived exertion (RPE) (P = 0.030) revealed that RPE values were significantly higher in the 8 kg slow cadence condition compared to the 4 kg slow (P = 0.002) and 4 kg fast (P = 0.016) conditions. In summary, this study indicates that the physiological and mechanical responses to kettlebell swings at 4 kg and 8 kg loads and at fast and slow cadence were similar, whereas the perceptual response is greater when swinging an 8 kg kettlebell at slow cadence.
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Less Is More: The Physiological Basis for Tapering in Endurance, Strength, and Power Athletes
Kevin A. Murach and James R. Bagley
Pages 209–218
Abstract: Taper, or reduced-volume training, improves competition performance across a broad spectrum of exercise modes and populations. This article aims to highlight the physiological mechanisms, namely in skeletal muscle, by which taper improves performance and provide a practical literature-based rationale for implementing taper in varied athletic disciplines. Special attention will be paid to strength- and power-oriented athletes as taper is under-studied and often overlooked in these populations. Tapering can best be summarized by the adage “less is more” because maintained intensity and reduced volume prior to competition yields significant performance benefits.
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Recommendations for Recruiting and Retaining Adolescent Girls in Chronic Exercise (Training) Research Studies
Rachel Massie, Brett Smith and Keith Tolfrey
Åtages 219–235
Abstract: Extensive challenges are often encountered when recruiting participants to chronic exercise (training) studies. High participant burden during chronic exercise training programmes can result in low uptake to and/or poor compliance with the study. The aim of this qualitative study was to identify factors affecting adolescent girls’ recruitment and adherence to chronic exercise training research studies. Twenty-six adolescent girls (aged 12 to 15 years) participated in one of five focus groups discussing recruitment and retention to exercise physiology research involving a chronic exercise training programme. A thematic analysis was used to analyse the data and eight final themes were inductively identified. Seven evidence-based practical recommendations are suggested to improve the recruitment and retention of participants for prospective, chronic exercise training studies. Successful recruitment requires: (i) the defining of exercise-related terms; (ii) appropriate choice of recruitment material; and (iii) an understanding of participant motivations. Retention strategies include: (iv) regular monitoring of participant motives; and (v) small groups which foster peer and researcher support. Finally, (vi) friendship and ability groups were favoured in addition to (vii) a variety of activities to promote adherence to an exercise training programme.
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Angle Specific Analysis of Side-to-Side Asymmetry in the Shoulder Rotators
Cassio V. Ruas, Ronei S. Pinto, Eduardo L. Cadore and Lee E. Brown
Pages 236–245
Abstract: Although side-to-side asymmetry of the shoulder rotators calculated by independent peak torque (IPT) has been used for interpretation of injury risks in athletes, it may not measure strength through the entire range of motion (ROM) tested. The aim of this study was to compare side-to-side asymmetry of the shoulder rotators between independent peak torque (IPT) and ten-degree angle specific torque (AST). Twenty healthy adult males (24.65 ± 2.4 years) performed concentric and eccentric internal rotation (IR) and external rotation (ER) of the preferred and non-preferred arms on an isokinetic dynamometer at 60°/s through 150° of total ROM. The total ROM was divided into 14 ten-degree angles of the physiological ROM from −90° of ER to 60° of IR. Concentric and eccentric IR IPT (10.5% ± 8.7% and 12.1% ± 7.2%) and ER IPT (13.6% ± 9.8% and 8.7% ± 5.6%) were significantly less than AST at several angles (p < 0.05). IPT might lead to erroneous interpretations of side-to-side asymmetry in the shoulder rotators and does not represent the entire ROM tested. This information could be used to prescribe strength exercises to enhance overhead performance and reduce risk of shoulder injuries.
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Kinematics and Kinetics of Youth Baseball Catchers and Pitchers
Gretchen Oliver, Keith Lohse and Sarah Gascon
Pages 246–257
Abstract: The purpose of this study was to compare the throwing kinematics and kinetics of youth catchers and pitchers. It was hypothesized that catchers and pitchers would exhibit differences throughout the throwing motion. Descriptive statistics were used to investigate kinematics during the four events of throwing: foot contact (FC), maximum shoulder external rotation (MER), ball release (BR) and maximum shoulder internal rotation (MIR). Additionally, kinetics were investigated within phases of the events: Phase 1 (cocking; FC to MER), Phase 2 (acceleration; MER to BR) and Phase 3 (deceleration; BR to MIR). Results revealed significant difference in torso flexion, lateral flexion, pelvis lateral flexion and segment velocities between the catchers and pitchers. Based on data from the current study, it appears that the youth catchers execute their throw as they have been instructed. It is unclear if the throwing mechanics displayed by these youth are efficient for a catcher, thus further investigation is needed to determine long-term injury susceptibility.
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Effectiveness of Different Rest Intervals Following Whole-Body Vibration on Vertical Jump Performance between College Athletes and Recreationally Trained Females
Nicole C. Dabbs, Jon A. Lundahl and John C. Garner
Pages 258–268
Abstract: The purpose of this study was to evaluate the effect of different rest intervals following whole-body vibration on counter-movement vertical jump performance. Sixteen females, eight recreationally trained and eight varsity athletes volunteered to participate in four testing visits separated by 24 h. Visit one acted as a familiarization visit where subjects were introduced to the counter-movement vertical jump and whole-body vibration protocols. Visits 2–4 contained 2 randomized conditions. Whole-body vibration was administered in four bouts of 30 s with 30 s rest between bouts. During whole-body vibration subjects performed a quarter squat every 5 s, simulating a counter-movement vertical jump. Whole-body vibration was followed by three counter-movement vertical jumps with five different rest intervals between the vibration exposure and jumping. For a control condition, subjects performed squats with no whole-body vibration. There was a significant (p < 0.05) main effect for time for vertical jump height, peak power output, and relative ground reaction forces, where a majority of individuals max jump from all whole-body vibration conditions was greater than the control condition. There were significant (p < 0.05) group differences, showing that varsity athletes had a greater vertical jump height and peak power output compared to recreationally trained females. There were no significant (p > 0.05) group differences for relative ground reaction forces. Practitioners and/or strength and conditioning coaches may utilize whole-body vibration to enhance acute counter-movement vertical jump performance after identifying individuals optimal rest time in order to maximize the potentiating effects.
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Individual Responses for Muscle Activation, Repetitions, and Volume during Three Sets to Failure of High- (80% 1RM) versus Low-Load (30% 1RM) Forearm Flexion Resistance Exercise
Nathaniel D. M. Jenkins, Terry J. Housh, Samuel L. Buckner, Haley C. Bergstrom, Kristen C. Cochrane, Cory M. Smith, Ethan C. Hill, Richard J. Schmidt and Joel T. Cramer
Pages 269–280
Abstract: This study compared electromyographic (EMG) amplitude, the number of repetitions completed, and exercise volume during three sets to failure of high- (80% 1RM) versus low-load (30% 1RM) forearm flexion resistance exercise on a subject-by-subject basis. Fifteen men were familiarized, completed forearm flexion 1RM testing. Forty-eight to 72 h later, the subjects completed three sets to failure of dumbbell forearm flexion resistance exercise with 80% (n = 8) or 30% (n = 7) 1RM. EMG amplitude was calculated for every repetition, and the number of repetitions performed and exercise volume were recorded. During sets 1, 2, and 3, one of eight subjects in the 80% 1RM group demonstrated a significant linear relationship for EMG amplitude versus repetition. For the 30% 1RM group, seven, five, and four of seven subjects demonstrated significant linear relationships during sets 1, 2, and 3, respectively. The mean EMG amplitude responses show that the fatigue-induced increases in EMG amplitude for the 30% 1RM group and no change in EMG amplitude for the 80% 1RM group resulted in similar levels of muscle activation in both groups. The numbers of repetitions completed were comparatively greater, while exercise volumes were similar in the 30% versus 80% 1RM group. Our results, in conjunction with those of previous studies in the leg extensors, suggest that there may be muscle specific differences in the responses to high- versus low-load exercise.
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Outcomes following Hip and Quadriceps Strengthening Exercises for Patellofemoral Syndrome: A Systematic Review and Meta-Analysis
Adebisi Bisi-Balogun and Firdevs Torlak
Pages 281–301
Abstract: There is growing evidence to support change in the rehabilitation strategy of patellofemoral pain syndrome (PFPS) from traditional quadriceps strengthening exercises to inclusion of hip musculature strengthening in individuals with PFPS. Several studies have evaluated effects of quadriceps and hip musculature strengthening on PFPS with varying outcomes on pain and function. This systematic review and meta-analysis aims to synthesize outcomes of pain and function post-intervention and at follow-up to determine whether outcomes vary depending on the exercise strategy in both the short and long term. Electronic databases including MEDLINE, EMBASE, CINAHL, Web of Science, PubMed, Pedro database, Proquest, Science direct, and EBscoHost databases were searched for randomized control trials published between 1st of January 2005 and 31st of June 2015, comparing the outcomes of pain and function following quadriceps strengthening and hip musculature strengthening exercises in patients with PFPS. Two independent reviewers assessed each paper for inclusion and quality. Means and SDs were extracted from each included study to allow effect size calculations and comparison of results. Six randomized control trials met the inclusion criteria. Limited to moderate evidence indicates that hip abductor strengthening was associated with significantly lower pain post-intervention (SMD −0.88, −1.28 to −0.47 95% CI), and at 12 months (SMD −3.10, −3.71 to −2.50 95% CI) with large effect sizes (greater than 0.80) compared to quadriceps strengthening. Our findings suggest that incorporating hip musculature strengthening in management of PFPS tailored to individual ability will improve short-term and long-term outcomes of rehabilitation. Further research evaluating the effects of quadriceps and hip abductors strengthening focusing on reduction in anterior knee pain and improvement in function in management of PFPS is needed.
It’s Not Me, It’s You: The Disconnect of Physical Education Teachers to Physical Activity in the Gym
Dean Culpepper and Lorraine Killion
Pages 302–311
Abstract: American adults and an increasing number of children, are not meeting the recommended amounts of daily physical activity. Research has documented the effects of low activity on health and increasingly new research has shown that low activity levels now impact academic achievement. Physical education (PE) can play an important role if the children participating are obtaining enough physical activity while in class and the PE program has not been targeted with cutbacks. The purpose of this study was to identify the amount and intensity of activity in PE classes. The results indicate that on average students at all levels are not meeting the activity requirements. In addition, PE teachers’ perceptions of physical activity in their own class does not match actual activity levels. PE teachers must do a better job of increasing activity levels in their classrooms. Mounting research indicates students perform better academically if they are physically active. PE is the only subject where teachers can organize activities that meet both activity and intensity requirements.
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Effects of Respiratory Muscle Warm-up on High-Intensity Exercise Performance
Taylor S. Thurston, Jared W. Coburn, Lee E. Brown, Albert Bartolini, Tori L. Beaudette, Patrick Karg, Kathryn A. McLeland, Jose A. Arevalo, Daniel A. Judelson and Andrew J. Galpin
Pages 312–32
Abstract: Exercise performance is partially limited by the functionality of the respiratory musculature. Training these muscles improves steady-state exercise performance. However, less is known about the efficacy of executing a respiratory muscle warm-up (RWU) immediately prior to high-intensity exercise. Our study purpose was to use a practitioner-friendly airflow restriction device to investigate the effects of a high, medium, or low intensity RWU on short, high-intensity exercise and pulmonary, cardiovascular, and metabolic function. Eleven recreationally active, males (24.9 ± 4.2 y, 178.8 ± 9.0 cm, 78.5 ± 10.4 kg, 13.4% ± 4.2% body fat) cycled at 85% peak power to exhaustion (TTE) following four different RWU conditions (separate days, in random order): (1) high; (2) medium; (3) low airflow inspiration restriction, or no RWU. When analyzed as a group, TTE did not improve following any RWU (4.73 ± 0.33 min). However, 10 of the 11 participants improved ≥25 s in one of the three RWU conditions (average = 47.6 ± 13.2 s), which was significantly better than (p < 0.05) the control trial (CON). Neither blood lactate nor perceived difficulty was altered by condition. In general, respiratory exchange ratios were significantly lower during the early stages of TTE in all RWU conditions. Our findings suggest RWU efficacy is predicated on identifying optimal inspiration intensity, which clearly differs between individuals.
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A Comparison between Learning Style Preferences, Gender, Sport and Achievement in Elite Team Sport Athletes
Andrea Braakhuis, Tea Williams, Elizabeth Fusco, Shawn Hueglin and Alex Popple
Pages 325–334
Abstract: Athletes have preferences for the way in which they internalize and process information, whether that is visual, aural, by-doing (kinesthetic), reading or a mixture of preferences. Health professionals that interact with athletes rarely consider the individual learning style prior to any communication or education, despite mounting evidence for the benefits of learning-style tailored education. The aim of this study was to characterize athletes with regards to their preferred learning style. Athletes (n = 93) from 24 sports and various sport achievement levels completed a questionnaire, including the visual (V), auditory (A), reading/writing (R), kinesthetic (K)/(VARK) Questionnaire for Athletes. Questionnaire outcomes were analysed by X2 analysis on SPSS. The main findings were: (1) very few athletes have a visual learning-style preference; (2) there was a significant relationship between gender and VARK preference (X2 = 13.84, p = 0.003); (3) and between athletic status and VARK preference (X2 = 9.2, p = 0.025); (4) there was a trivial association between individual/ team sport athletes and assessed VARK preference (X2 = 3.95, p = 0.265). Our findings show significant variation in learning-style preference between males and females, and those of different athletic status. Health professionals should be aware of the inadequacy of visual information presentation when working with athletes. Furthermore, health professionals working with elite and female athletes should be comfortable using a mixture of learning styles (multi-modal).
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Using Rowers’ Perceptions of On-Water Stroke Success to Evaluate Sculling Catch Efficiency Variables via a Boat Instrumentation System
Sarah-Kate Millar, Anthony R. H. Oldham, Patria A. Hume and Ian Henshaw
Pages 335–345
Abstract: Aim: An effective catch in sculling is a critical determinant of boat velocity. This study used rowers’ performance-based judgments to compare three measures of catch slip efficiency. Two questions were addressed: (1) would rower-judged Yes strokes be faster than No strokes? and (2) which method of quantifying catch slip best reflected these judgements? Methods: Eight single scullers performed two 10-min blocks of sub maximal on-water rowing at 20 strokes per minute. Every 30 s, rowers reported either Yes or No about the quality of their stroke at the catch. Results: It was found that Yes strokes identified by rowers had, on average, a moderate effect advantage over No strokes with a standardised effect size of 0.43. In addition, a quicker time to positive acceleration best reflected the change in performance; where the standardised mean difference score of 0.57 for time to positive acceleration was larger than the scores of 0.47 for time to PowerLine force, and 0.35 for time to 30% peak pin force catch slip measures. For all eight rowers, Yes strokes corresponded to time to positive acceleration occurring earlier than No strokes. Conclusion: Rower judgements about successful strokes was linked to achieving a quicker time to positive acceleration, and may be of the most value in achieving a higher average boat velocity.
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Is There a Progressive Withdrawal of Physiological Protections against High-Intensity Exercise-Induced Fatigue during Puberty?
Sébastien Ratel and Vincent Martin
Pages 346–357
Abstract: Puberty is characterized by a large number of physiological modifications that translate into increased neuromuscular fatigue during high-intensity exercise in adolescents compared to prepubertal children. This greater neuromuscular fatigue in adolescents could be attributed to peripheral (i.e., muscular) and central (i.e., nervous) factors that change through puberty. Among the peripheral changes are muscle mass, fiber type composition, energy metabolism and musculo-tendinous stiffness. Among the central modifications are the voluntary activation level, the antagonist co-activation and a differential interplay between central and peripheral fatigue. The objective of this review article will be to underline the importance of these factors on the development of neuromuscular fatigue during high-intensity exercise throughout puberty and to highlight that the adolescents could be physiologically less protected against fatiguing high-intensity exercise than their prepubertal counterparts.
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Reliability of the Single-Visit Field Test of Critical Speed in Trained and Untrained Adolescents
Alfred Nimmerichter, Mathias Steindl and Craig Anthony Williams
Pages 358–368
Abstract: Recent studies in adults have shown that the critical intensity during running and cycling estimated from three prediction trials interspersed by 30 min is valid and reliable. To establish the reliability of the single-visit field test to determine critical speed (CS) and the distance above critical speed (D′) in adolescents, 29 trained and 14 untrained participants (mean ± SD age: 17.5 ± 0.5 years) performed three tests on a 400-m outdoor track separated by 48 h. Each test consisted of three distances selected to result in finishing times between 2 and 15 min that must be completed as fast as possible. CS and D′ were modeled using the linear 1/time model (Speed = D′(1/t) + CS). While the coefficient of variation (CV) of CS was between 2.4% and 4.3%, the CV of D′ was 9.3% to 13.6%. Also the intraclass correlation coefficient ranged from 0.919 to 0.983 for CS and from 0.325 to 0.828 for D′. The results show that the single-visit field test provides reliable estimates of CS but not D′ in trained and untrained adolescents.
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Physiological Responses Underlying the Perception of Effort during Moderate and Heavy Intensity Cycle Ergometry
Kristen C. Cochrane, Terry J. Housh, Ethan C. Hill, Cory M. Smith, Nathaniel D.M. Jenkins, Joel T. Cramer, Glen O. Johnson and Richard J. Schmidt
Pages 369–382
Abstract: This study examined patterns of responses for physiological and perceptual variables during cycle ergometry at a constant rate of perceived exertion (RPE) within the moderate and heavy exercise intensity domains. Nineteen (mean age 21.3 ± 0.5 years; 43.4 ± 2.0 mL·kg−1·min−1 V ˙ O 2 Peak ) moderately trained cyclists performed an incremental test to exhaustion and two 60 min constant RPE rides at the RPE corresponding to the gas exchange threshold (RPEGET) and 15% above the GET (RPEGET+15%). Oxygen consumption ( V ˙ O2), respiratory exchange ratio (RER), heart rate (HR), minute ventilation ( V ˙ E ), breathing frequency ( ℱ b ), and power output (PO) were monitored throughout the rides. Polynomial regression analyses showed V ˙ O2, RER, HR, and V ˙ E (correlation = −0.85 to −0.98) tracked the decreases in PO required to maintain a constant RPE. Only ℱ b tracked RPE during the moderate and heavy intensity rides. Repeated measures ANOVAs indicated that V ˙ O2during the 60 min rides at RPEGET was not different (p > 0.05) from V ˙ O2 at GET from the incremental test to exhaustion. Thus, monitoring intensity using an RPE associated with the GET is sustainable for up to 60 min of cycling exercise and a common mechanism may mediate ℱ b and the perception of effort during moderate and heavy intensity cycle ergometry
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