Purpose: To examine the effects of different small-sided games (SSGs) on physical and technical aspects of performance in wheelchair basketball (WB) players. Design: Observational cohort study. Methods: Fifteen highly trained WB players participated in a single 5v5 (24-s shot clock) match and three 3v3 SSGs (18-s shot clock) on a (1) full court, (2) half-court, and (3) modified-length court. During all formats, players’ activity profiles were monitored using an indoor tracking system and inertial measurement units. Physiological responses were monitored via heart rate and rating of perceived exertion. Technical performance, that is, ball handling, was monitored using video analysis. Repeated-measures analysis of variance and effect sizes (ESs) were calculated to determine the statistical significance and magnitude of any differences between game formats. Results: Players covered less distance and reached lower peak speeds during half-court (P ≤ .0005; ES ≥ very large) compared with all other formats. Greater distances were covered, and more time was spent performing moderate- and high-speed activity (P ≤ .008; ES ≥ moderate) during full court compared with all other formats. Game format had little bearing on physiological responses, and the only differences in technical performance observed were in relation to 5v5. Players spent more time in possession, took more shots, and performed more rebounds in all 3v3 formats compared with 5v5 (P ≤ .028; ES ≥ moderate). Conclusions: Court dimensions affect the activity profiles of WB players during 3v3 SSGs yet had little bearing on technical performance when time pressures (shot clocks) were constant. These findings have important implications for coaches to understand which SSG format may be most suitable for physically and technically preparing WB players.
Barry S. Mason, Rienk M.A. van der Slikke, Michael J. Hutchinson, Monique A.M. Berger and Victoria L. Goosey-Tolfrey
Kathryn L. Beck, Sarah Mitchell, Andrew Foskett, Cathryn A Conlon and Pamela R. Von Hurst
Ballet dancing is a multifaceted activity requiring muscular power, strength, endurance, flexibility, and agility; necessitating demanding training schedules. Furthermore dancers may be under aesthetic pressure to maintain a lean physique, and adolescent dancers require extra nutrients for growth and development. This cross-sectional study investigated the nutritional status of 47 female adolescent ballet dancers (13–18 years) living in Auckland, New Zealand. Participants who danced at least 1 hr per day 5 days per week completed a 4-day estimated food record, anthropometric measurements (Dual-energy X-ray Absorptiometry) and hematological analysis (iron and vitamin D). Mean BMI was 19.7 ± 2.4kg/m2 and percentage body fat, 23.5 ± 4.1%. The majority (89.4%) of dancers had a healthy weight (5th-85th percentile) using BMI-for-age growth charts. Food records showed a mean energy intake of 8097.3 ± 2155.6kJ/day (48.9% carbohydrate, 16.9% protein, 33.8% fat, 14.0% saturated fat). Mean carbohydrate and protein intakes were 4.8 ± 1.4 and 1.6 ± 0.5g/kg/day respectively. Over half (54.8%) of dancers consumed less than 5g carbohydrate/kg/day, and 10 (23.8%) less than 1.2 g protein/kg/day. Over 60% consumed less than the estimated average requirement for calcium, folate, magnesium and selenium. Thirteen (28.3%) dancers had suboptimal iron status (serum ferritin (SF) <20μg/L). Of these, four had iron deficiency (SF < 12μg/L, hemoglobin (Hb) ≥ 120g/L) and one iron deficiency anemia (SF < 12μg/L, Hb < 120g/L). Mean serum 25-hydroxy vitamin D was 75.1 ± 18.6nmol/L, 41 (91.1%) had concentrations above 50nmol/L. Female adolescent ballet dancers are at risk for iron deficiency, and possibly inadequate nutrient intakes.
Mark Elisabeth Theodorus Willems, Stephen David Myers, Mandy Lucinda Gault and Matthew David Cook
Blackcurrant contains anthocyanins, known to influence vasorelaxation and peripheral blood flow. We examined the effects of 7 days intake of Sujon New Zealand blackcurrant powder (6g/day) on the lactate curve, maximum oxygen uptake, and cardiovascular responses at rest and during cycling. Thirteen trained triathletes with >3 yrs experience (8 men, age: 38 ± 8 yrs, body mass: 71 ± 9 kg, BF%: 19 ± 5%, mean ± SD) performed two incremental cycling protocols with recording of physiological and cardiovascular responses (Portapres Model 2). Cardiovascular function was also measured in rest. Experimental design was doubleblind, placebo-controlled, randomized and cross-over (wash-out 4 wks). Data were analyzed with two-tailed t tests and 2-way ANOVA and significance accepted at p < .05. Plasma lactate was lower at 40%, 50%, 60% and 70% of maximum power by 27%, 22%, 17% and 13%. Intensity at 4 mmol·L-1 OBLA was 6% higher with blackcurrant without effect on heart rate and oxygen uptake. Maximum values of oxygen uptake, heart rate and power were not affected by blackcurrant, but obtained with 14% lower lactate. In rest, blackcurrant increased stroke volume and cardiac output by 25% and 26%, and decreased total peripheral resistance by 16%, with no changes in blood pressure and heart rate. Cardiovascular responses during exercise at 40%, 50%, 60%, 70% and 80% intensity were not affected. Sujon New Zealand blackcurrant powder affects lactate production and/or clearance during exercise. Sujon New Zealand blackcurrant powder affects physiological and cardiovascular responses in rest and during exercise that may have implications for exercise performance.
Brandon M. Kistler, Peter J. Fitschen, Sushant M. Ranadive, Bo Fernhall and Kenneth R. Wilund
The purpose of this study was to document the physiological changes that occur in a natural bodybuilder during prolonged contest preparation for a proqualifying contest. During the 26-week preparation, the athlete undertook a calorically restrictive diet with 2 days of elevated carbohydrate intake per week, increased cardiovascular (CV) training, and attempted to maintain resistance-training load. The athlete was weighed twice a week and body composition was measured monthly by DXA. At baseline and every 2 weeks following CV structure and function was measured using a combination of ultrasound, applanation tonometry, and heart rate variability (HRV). Cardiorespiratory performance was measured by VO2peak at baseline, 13 weeks, and 26 weeks. Body weight (88.6 to 73.3 Kg, R 2 = .99) and percent body fat (17.5 to 7.4%) were reduced during preparation. CV measurements including blood pressure (128/61 to 113/54mmHg), brachial pulse wave velocity (7.9 to 5.8m/s), and measures of wave reflection all improved. Indexed cardiac output was reduced (2.5 to 1.8L/m2) primarily due to a reduction in resting heart rate (71 to 44bpm), and despite an increase in ejection faction (57.9 to 63.9%). Assessment of HRV found a shift in the ratio of low to high frequency (209.2 to 30.9%). Absolute VO2 was minimally reduced despite weight loss resulting in an increase in relative VO2 (41.9 to 47.7ml/Kg). In general, this prolonged contest preparation technique helped the athlete to improve body composition and resulted in positive CV changes, suggesting that this method of contest preparation appears to be effective in natural male bodybuilders.
Martin J. Turner and Alberto P. Avolio
International guidelines suggest limiting sodium intake to 86–100 mmol/day, but average intake exceeds 150 mmol/day. Participants in physical activities are, however, advised to increase sodium intake before, during and after exercise to ensure euhydration, replace sodium lost in sweat, speed rehydration and maintain performance. A similar range of health benefits is attributable to exercise and to reduction in sodium intake, including reductions in blood pressure (BP) and the increase of BP with age, reduced risk of stroke and other cardiovascular diseases, and reduced risk of osteoporosis and dementia. Sweat typically contains 40–60 mmol/L of sodium, leading to approximately 20–90 mmol of sodium lost in one exercise session with sweat rates of 0.5–1.5 L/h. Reductions in sodium intake of 20–90 mmol/day have been associated with substantial health benefits. Homeostatic systems reduce sweat sodium as low as 3–10 mmol/L to prevent excessive sodium loss. “Salty sweaters” may be individuals with high sodium intake who perpetuate their “salty sweat” condition by continual replacement of sodium excreted in sweat. Studies of prolonged high intensity exercise in hot environments suggest that sodium supplementation is not necessary to prevent hyponatremia during exercise lasting up to 6 hr. We examine the novel hypothesis that sodium excreted in sweat during physical activity offsets a significant fraction of excess dietary sodium, and hence may contribute part of the health benefits of exercise. Replacing sodium lost in sweat during exercise may improve physical performance, but may attenuate the long-term health benefits of exercise.
Colin R. Carriker, Christine M. Mermier, Trisha A. VanDusseldorp, Kelly E. Johnson, Nicholas M. Beltz, Roger A. Vaughan, James J. McCormick, Nathan H. Cole, Christopher C. Witt and Ann L. Gibson
Reduced partial pressure of oxygen impairs exercise performance at altitude. Acute nitrate supplementation, at sea level, may reduce oxygen cost during submaximal exercise in hypobaric hypoxia. Therefore, we investigated the metabolic response during exercise at altitude following acute nitrate consumption. Ten well-trained (61.0 ± 7.4 ml/kg/min) males (age 28 ± 7 yr) completed 3 experimental trials (T1, T2, T3). T1 included baseline demographics, a maximal aerobic capacity test (VO2max) and five submaximal intensity cycling determination bouts at an elevation of 1600 m. A 4-day dietary washout, minimizing consumption of nitrate-rich foods, preceded T2 and T3. In a randomized, double-blind, placebo-controlled, crossover fashion, subjects consumed either a nitrate-depleted beetroot juice (PL) or ~12.8 mmol nitrate rich (NR) beverage 2.5 hr before T2 and T3. Exercise at 3500 m (T2 and T3) via hypobaric hypoxia consisted of a 5-min warm-up (25% of normobaric (VO2max) and four 5-min cycling bouts (40, 50, 60, 70% of normobaric VO2max) each separated by a 4-min rest period. Cycling RPM and watts for each submaximal bout during T2 and T3 were determined during T1. Preexercise plasma nitrite was elevated following NR consumption compared with PL (1.4 ± 1.2 and 0.7 ± 0.3 uM respectively; p < .05). There was no difference in oxygen consumption (−0.5 ± 1.8, 0.1 ± 1.7, 0.7 ± 2.1, and 1.0 ± 3.0 ml/kg/min) at any intensity (40, 50, 60, 70% of VO2max), respectively) between NR and PL. Further, respiratory exchange ratio, oxygen saturation, heart rate and rating of perceived exertion were not different at any submaximal intensity between NR and PL either. Blood lactate, however, was reduced following NR consumption compared with PL at 40 and 60% of VO2max (p < .0.05). Our findings suggest that acute nitrate supplementation before exercise at 3500 m does not reduce oxygen cost but may reduce blood lactate accumulation at lower intensity workloads.
Suzanna Russell, Angus G. Evans, David G. Jenkins and Vincent G. Kelly
. Monitored through electrocardiography and pulse plethysmography, ECP is believed to augment the magnitude of cardiac output and venous return by inducing more favorable distal to proximal pressure differentials within the cardiovascular system. A potential advantage of ECP as an effective recovery method is
Ryan G. Overmayer and Matthew W. Driller
garments; by exerting up to 4 times greater levels of pressure (∼80 mm Hg) to the applied area, when compared with commercially available compression garments. 11 In addition, ISPC mimics the anatomical muscle venous pump by providing a mechanical “squeezing” of the limb through inflatable cuffs
Denise M. Hill, Matthew Cheesbrough, Paul Gorczynski and Nic Matthews
of pressure ( Hill, Carvell, Matthews, Thelwell, & Weston, 2017 ; Hill, Hanton, Matthews, & Fleming, 2010a ). The most recent definition provided by Mesagno and Hill ( 2013 ) suggests that choking is “an acute and considerable decrease in skill execution and performance, when self-expected standards
Llion A. Roberts, Johnpaul Caia, Lachlan P. James, Tannath J. Scott and Vincent G. Kelly
pneumatic compression (IPC) garments, which aligns with the current popularity of this therapy within the worldwide athletic community. Such IPC garments are worn on the arms and/or legs, with a methodological principle based on applying rhythmic, time-gated pressures ranging from 60 to 80 mm Hg 6 – 8