The body composition of a squash player may affect athletic performance as carrying excessive body fat may increase injury risk and impair agility and speed. This case study outlines the effect of a nutritional intervention on body composition, vitamin D status, and physical performance of a female squash player. A structured, 6-week, moderate energy–restricted diet (70–78% of estimated energy requirement of 2,300 kcal) was implemented with weekly support. A daily supplement of vitamin D, omega-3 fatty acids, and a multivitamin and whey protein was used. Full blood count, vitamin D status, body composition, and physical performance assessments were carried out at baseline and Week 6 of intervention. Body composition changes were measured using the BOD POD™ and skinfold calipers. Body fat was 23% at baseline and 22% at Week 6. Mean sum of eight skinfolds was 127.4 ± 2.2 mm at baseline and 107.3 ± 0.4 mm at Week 6. Lean body mass-to-fat mass ratio improved from 3.4 at baseline to 3.7 at Week 6. The greatest increments compared with baseline in serum markers were 25-hydroxyvitamin D3 (68%), ferritin (31%), eosinophils (20%), and triglycerides (16%). All physical performance measures improved, with reactive strength index (4.8%), and on-court repeated speed (6.0%) showing the greatest improvements from baseline. This intervention demonstrates that structured energy restriction alongside appropriately structured strength and conditioning training is an effective way to gradually reduce the body fat and improve the body composition of a female athlete.
Randy J. Schmitz, John C. Cone, Timothy J. Copple, Robert A. Henson and Sandra J. Shultz
Potential biomechanical compensations allowing for maintenance of maximal explosive performance during prolonged intermittent exercise, with respect to the corresponding rise in injury rates during the later stages of exercise or competition, are relatively unknown.
To identify lower-extremity countermovement-jump (CMJ) biomechanical factors using a principal-components approach and then examine how these factors changed during a 90-min intermittent-exercise protocol (IEP) while maintaining maximal jump height.
Fifty-nine intermittent-sport athletes (30 male, 29 female) participated in experimental and control conditions.
Before and after a dynamic warm-up and every 15 min during the 1st and 2nd halves of an individually prescribed 90-min IEP, participants were assessed on rating of perceived exertion, sprint/cut speed, and 3-dimensional CMJ biomechanics (experimental). On a separate day, the same measures were obtained every 15 min during 90 min of quiet rest (control).
Main Outcome Measures:
Univariate piecewise growth models analyzed progressive changes in CMJ performance and biomechanical factors extracted from a principal-components analysis of the individual biomechanical dependent variables.
While CMJ height was maintained during the 1st and 2nd halves, the body descended less and knee kinetic and energetic magnitudes decreased as the IEP progressed.
The results indicate that vertical-jump performance is maintained along with progressive biomechanical changes commonly associated with decreased performance. A better understanding of lower-extremity biomechanics during explosive actions in response to IEP allows us to further develop and individualize performance training programs.
Robert J. Aughey
Australian football (AF) is a highly intermittent sport, requiring athletes to accelerate hundreds of times with repeated bouts of high-intensity running (HIR). Players aim to be in peak physical condition for finals, with anecdotal evidence of increased speed and pressure of these games.
However, no data exists on the running demands of finals games, and therefore the aim of this study was to compare the running demands of finals to regular season games with matched players and opponents.
Player movement was recorded by GPS at 5 Hz and expressed per period of the match (rotation), for total distance, high-intensity running (HIR, 4.17-10.00 m·s-1) and maximal accelerations (2.78-10.00 m·s–2). All data was compared for regular season and finals games and the magnitude of effects was analyzed with the effect size (ES) statistic and expressed with confidence intervals.
Each of the total distance (11%; ES: 0.78 ± 0.30), high-intensity running distance (9%; ES: 0.29 ± 0.25) and number of maximal accelerations (97%; ES: 1.30 ± 0.20) increased in finals games. The largest percentage increases in maximal accelerations occurred from a commencement velocity of between 3–4 (47%; ES: 0.56 ± 0.21) and 4–5 m·s-1 (51%; ES: 0.72 ± 0.26), and with <19 s between accelerations (53%; ES: 0.63 ± 0.27).
Elite AF players nearly double the number of maximal accelerations in finals compared with regular season games. This large increase is superimposed on requirements to cover a greater total distance and spend more time at high velocity during finals games. Players can be effectively conditioned to cope with these increased demands, even during a long competitive season.
Kelsey Dow, Robert Pritchett, Karen Roemer and Kelly Pritchett
( Dziedzic & Higham, 2014 ). Due to a heavy reliance on carbohydrates as a fuel source during high-intensity exercise such as intermittent sport competition, post-exercise replenishment of carbohydrate stores immediately following each competition is vital. Current recovery nutrition recommendations suggest
Adam Beard, John Ashby, Ryan Chambers, Franck Brocherie and Grégoire P. Millet
Rugby union is an intermittent sport often having periods of high-intensity efforts with incomplete recoveries. 1 Total distances reported in the literature have ranged between 4800 and 5200 m for forwards and 5600 and 6000 m for backs, 2 whereas sprint distances have ranged between 350 and 510 m
Petros G. Botonis, Ioannis Malliaros, Gavriil G. Arsoniadis, Theodoros I. Platanou and Argyris G. Toubekis
Water polo is an intermittent sport that encompasses high-intensity efforts of short duration alternating with longer periods of low-intensity movements. 1 , 2 It has been reported that the overall exercise intensity during a competitive water polo game corresponds to players’ lactate threshold, 3
Mayur K. Ranchordas, George King, Mitchell Russell, Anthony Lynn and Mark Russell
). Collectively, these improvements could enhance performance in soccer as it is a physically demanding intermittent sport that stresses both anaerobic and aerobic energy systems. During a match, players are involved in soccer-specific actions requiring repeated high-intensity running and high endurance capacity
Mitchell J. Henderson, Job Fransen, Jed J. McGrath, Simon K. Harries, Nick Poulos and Aaron J. Coutts
elite rugby sevens players? Presented at the 17th Annual Congress of the European College of Sport Science ; 2012 . Bruges, Belgium . 6. Buchheit M . The 30–15 intermittent fitness test: accuracy for individualizing interval training of young intermittent sport players . J Strength Cond Res
Tannath J. Scott, Heidi R. Thornton, Macfarlane T.U. Scott, Ben J. Dascombe and Grant M. Duthie
individualizing interval training of young intermittent sport players . J Strength Cond Res . 2008 ; 22 ( 2 ): 365 – 374 . PubMed doi:10.1519/JSC.0b013e3181635b2e 10.1519/JSC.0b013e3181635b2e 18550949 18. Buchheit M , Al Haddad H , Millet GP , Lepretre PM , Newton M , Ahmaidi S
Nick B. Murray, Tim J. Gabbett and Andrew D. Townshend
Australian football (AF) is a fast-paced, highly intermittent sport requiring players to perform high-intensity activities (ie, sprinting, running, and physical contacts) interspersed with low-speed (ie, walking and jogging) movements. 1 , 2 It is common practice in elite sporting organizations to