Effect of sodium phosphate supplementation on repeated high-intensity cycling efforts.

Limited research has investigated how sodium phosphate supplementation affects exercise performance typical of athletic competition and whether any effects linger in the short term. This study examined the effect of sodium phosphate supplementation on a cycling protocol consisting of repeated-sprint (4 sets of 6 × 15 s) and time-trial (2 × 5 min) efforts on day 1 and 4 post-loading. Trained male cyclists (VO(2peak) 5.3 L · min⁻¹) were randomised to 6 days of sodium phosphate supplementation (50 mg · kg·fat-free-mass⁻¹ · day⁻¹; n = 7) or placebo (n = 10). Performance was assessed at baseline and 1 and 4 days post-supplementation on an air-braked cycle ergometer. Compared with baseline, the sodium phosphate group recorded significantly improved (P < 0.05) work and mean power output values in both the sprint (baseline, 259 kJ/719 W; day 1, 271 kJ/754 W; day 4, 271 kJ/753 W) and time-trial (baseline, 225 kJ/374 W; day 1, 235 kJ/398 W; day 4, 236 kJ/393 W) aspects of the performance test post-loading. In the placebo group, no differences (P > 0.05) in total work or power output were noted in response to supplementation. In summary, sodium phosphate supplementation improved repeated-sprint and time-trial cycling efforts both 1 and 4 days post-loading in trained cyclists.

High-intensity intermittent exercise attenuates ad-libitum energy intake.

OBJECTIVE: To examine the acute effects of high-intensity intermittent exercise (HIIE) on energy intake, perceptions of appetite and appetite-related hormones in sedentary, overweight men. DESIGN: Seventeen overweight men (body mass index: 27.7±1.6 kg m(-2); body mass: 89.8±10.1 kg; body fat: 30.0±4.3%; VO(2peak): 39.2±4.8 ml kg(-1) min(-1)) completed four 30-min experimental conditions using a randomised counterbalanced design. CON: resting control, MC: continuous moderate-intensity exercise (60% VO(2peak)), HI: high-intensity intermittent exercise (alternating 60 s at 100% VO(2peak) and 240 s at 50% VO(2peak)), VHI: very-high-intensity intermittent exercise (alternating 15 s at 170% VO(2peak) and 60 s at 32% VO(2peak)). Participants consumed a standard caloric meal following exercise/CON and an ad-libitum meal 70 min later. Capillary blood was sampled and perceived appetite assessed at regular time intervals throughout the session. Free-living energy intake and physical activity levels for the experimental day and the day after were also assessed. RESULTS: Ad-libitum energy intake was lower after HI and VHI compared with CON (P=0.038 and P=0.004, respectively), and VHI was also lower than MC (P=0.028). Free-living energy intake in the subsequent 38 h remained less after VHI compared with CON and MC (P≤0.050). These observations were associated with lower active ghrelin (P≤0.050), higher blood lactate (P≤0.014) and higher blood glucose (P≤0.020) after VHI compared with all other trials. Despite higher heart rate and ratings of perceived exertion (RPE) during HI and VHI compared with MC (P≤0.004), ratings of physical activity enjoyment were similar between all the exercise trials (P=0.593). No differences were found in perceived appetite between trials. CONCLUSIONS: High-intensity intermittent exercise suppresses subsequent ad-libitum energy intake in overweight inactive men. This format of exercise was found to be well tolerated in an overweight population.

Burn-injured adults with long term functional impairments demonstrate the same response to resistance training as uninjured controls.

OBJECTIVE: The catabolic response associated with major burn injuries results in loss of lean body mass (LBM) and prolonged muscle weakness. Exercise training improves LBM and muscle strength in burn-injured children in the acute post injury phase, yet it is unknown whether adults will experience the same benefits when exercise training is implemented at least two years post injury. PROCEDURES: Nine burn-injured participants (%TBSA=42±18.38; time since injury=6.56±3.68 years) and 9 matched controls participated in a 12-week interval training and resistance exercise programme. Muscle strength was assessed via isokinetic dynamometry and LBM was determined via dual energy X-ray absorptiometry. Both measures were administered prior to and following the exercise programme. RESULTS: There was no significant difference in LBM or strength between the two groups at baseline. Following the exercise programme, both groups displayed significant improvements in LBM and in hip, shoulder and elbow muscle strength. There was no significant difference in muscle strength or LBM, between the groups, following the exercise training. CONCLUSION: A combined exercise training programme was able to improve muscle strength and lean body mass in adults with burn injury. There was no difference between the two groups in their response to the exercise programme, therefore general exercise prescription principles may be applied directly to the burns population.

Exercise training to improve health related quality of life in long term survivors of major burn injury: a matched controlled study.

OBJECTIVE: Patients often experience reduced health-related quality of life (HRQOL) following burn injury. Exercise training has been demonstrated to improve HRQOL in a number of clinical populations, yet it is unknown whether exercise can improve HRQOL in burns patients. PROCEDURES: Nine burn-injured participants (42±18.38%TBSA: 6.56±3.68 years after injury) and 9 matched controls participated in a 12-week exercise programme. HRQOL was assessed via the Burn Specific Health Scale-Brief (BSHS-B) and the Medical Outcomes Study 36-Item Short Form (SF-36). Activity limitation was measured using the quick Disabilities of the Arm, Shoulder and Hand (QuickDASH). RESULTS: The burns group had decreased HRQOL compared to the controls at baseline, as reported by the BSHS-B (t (16)=3.51, p=0.003) and some domains of the SF-36 including role physical (t (16)=3.79, p=0.002). Burned participants reported decreased activity levels compared to the controls as measured by the QuickDASH (t (16)=2.19, p=0.044). Exercise training improved SF-36 scores in both burn (t (8)=3.77, p=0.005) and control groups (t (8)=2.71, p=0.027). Following training there was no difference between the groups on the SF-36 or QuickDASH. CONCLUSION: Exercise training improves HRQOL and activity limitations in burn-injured patients to a level that is equivalent to that of their uninjured counterparts.

The effect of exercise training on pulmonary function and aerobic capacity in adults with burn.

PURPOSE: Pulmonary function (PF) is compromised in some individuals following burn, which may result in impaired aerobic capacity. Exercise training improves PF and exercise capacity in children recovering from burns, yet it is unknown if adults will demonstrate the same response. PROCEDURES: 9 burn injured participants (%TBSA 42 ±18.38, 6.56 years ±3.68 post injury) and 9 matched controls participated in a 12-week goal directed interval training and resistance exercise programme. PF was measured using spirometry, and a graded exercise test quantified peak oxygen consumption (Vo(2peak)), both prior to and following the exercise training. The Canadian Occupational Performance Measure assessed the participant's goal attainment. RESULTS: Burn injured participants had significantly lower PF (FEV(1)/FVC ratio) than the healthy controls both prior to and following the exercise intervention (F(1,16)=8.93, p=0.009). Exercise training did not improve PF in either group, however both groups had a significant improvement in their Vo(2peak), maximal minute ventilation, and work achieved on a graded exercise test (F(1,16)=19.325, p<0.001), (F(1,16)=51.417, p<0.001) and (F(1,16)=36.938, p<0.001), respectively, following the exercise training. All participants achieved their occupational performance goals. CONCLUSION: Although the exercise training did not alter PF, both aerobic capacity and occupational performance were improved.

Pulmonary function, exercise capacity and physical activity participation in adults following burn.

PURPOSE: To determine the relationship between pulmonary function, aerobic exercise capacity and physical activity participation in adults following burn. METHODS: Eight burn injured males aged 20-55 years (%TBSA 33.3±18.7, 5.1 years±1.8 post injury), and 30 healthy adult controls participated. Pulmonary function was assessed during rest via spirometry. A graded exercise test measuring peak oxygen consumption (VO(2peak)) and oxygen saturation (S(p)O(2)) was conducted, and physical activity was assessed via the Older Adult Exercise Status Inventory (OA-EI). RESULTS: No significant correlation was observed between resting pulmonary function, aerobic capacity and physical activity participation for burn injured patients or controls. Two burn injured patients presented with obstructive ventilatory defects, and one displayed a restrictive ventilatory defect. Burn injured patients had a significantly lower VO(2peak) (p<0.001) and time to fatigue (p=0.026), and a greater degree of oxygen desaturation (p=0.063, Effect Size=1.02) during a graded exercise test. Burn injured patients reported significantly less participation in leisure-related activity>9 METs (p=0.01), and significantly greater participation in work-related activity (p=0.038), than healthy controls. CONCLUSION: Compromised lung function, decreased aerobic capacity and reduced participation in leisure-related physical activity may still exist in some adults, even up to 5 years post injury. Limitations and long term outcomes of cardiopulmonary function and physical fitness need to be considered in the prescription of exercise rehabilitation programmes following burn.

Effects of caffeine on repeated sprint ability, reactive agility time, sleep and next day performance.

AIM: This study assessed the effects of caffeine on repeated sprint ability (RSA), reactive agility time (RAT), sleep and next day exercise performance. METHODS: Ten moderately trained male athletes (single-blind, randomized, crossover design) ingested either caffeine (6 mg.kg-1 bm) or placebo 1 h before exercise. Trials were performed on the same day one week apart. Performance measures included a RAT test (10 trials¥10.2 m, separated by 30 s), followed by 7 min of active recovery and then a RSA test (five sets of 6¥20 m sprints with 25 or 60 s of recovery). The RSA was then followed by 5 min of active recovery and another RAT. That night, participants wore a wrist sleep actigraph to bed. Next day, participants repeated the RAT and the first set of the RSA tests. RESULTS: Significant improvements were demonstrated after caffeine ingestion compared to placebo for the combined total time of each set (TT; combined sets 1, 3, 5; 58.947±1.88 vs. 59.683±2.54 s, respectively; P=0.05), best sprint time (BT; next day performance; 3.176±0.10 vs. 3.230±0.12 s, respectively, P=0.01), and % decrement (combined sets 2, 4; 2.866±1.24 vs. 3.801±1.69 s, respectively; P=0.02). Moderate to strong effect sizes were found for % decrement for set 2 (Cohen's d=-0.82; 1.312±0.65 vs. 2.110±1.20 s for caffeine and placebo conditions, respectively) and for sets 2 and 4 combined (Cohen's d=-0.63; 2.866±1.24 vs. 3.801±1.69 for caffeine and placebo conditions, respectively). No significant differences were found for RAT or for sleep measures (P>0.05). CONCLUSION: Caffeine improved RSA, including next day performance, but had little effect on RAT or sleep parameters.

Supervised home-based exercise may attenuate the decline of glucose tolerance in obese pregnant women.

AIM: The significant deterioration of insulin sensitivity and glucose tolerance during pregnancy can have serious health implications for both the pregnant woman and her baby. Although it is well established that regular exercise benefits insulin sensitivity in the nonpregnant population, the effect on glucose tolerance in obese pregnant women is not known. The purpose of this study was to investigate the effect of a supervised 10-week, home-based, exercise programme, beginning at week 18 of gestation, on glucose tolerance and aerobic fitness in previously sedentary obese women. METHODS: Twelve sedentary obese women were randomized into an exercise (EX; n=6) or control (CON; n=6) group at 18 weeks of gestation. Those randomized to EX engaged in 10 weeks of supervised home-based exercise (three sessions a week of stationary cycling), while those in the CON group maintained their usual daily activity. Their glucose and insulin responses to an oral glucose tolerance test (OGTT), as well as their aerobic fitness, were assessed both pre- and postintervention. RESULTS: Reduced glucose tolerance in the CON, but not EX, group was indicated by a tendency postintervention towards higher blood glucose levels at 1h of the OGTT (P=0.072). Furthermore, at 2h of the postintervention OGTT, blood glucose tended to remain elevated from baseline in the CON (P=0.077). There was also a trend towards increased fitness in the EX (P=0.064), but not the CON group. CONCLUSION: Regular aerobic exercise begun during pregnancy may have favourable effects on glucose tolerance and fitness in obese women, and warrants further investigation in a larger sample population.