Short-term effects of cycle and treadmill training on exercise tolerance in peripheral arterial disease

Background. To explore the efficacy of cycle training in the treatment of intermittent claudication, the present study compared performance and physiologic effects of cycle training with more conventional treadmill walking training in a group of patients with claudication. Method: Forty-two individuals with peripheral arterial disease and intermittent claudication (24 men, 18 women) were stratified by gender and the presence or absence of type 2 diabetes mellitus and then randomized to a treadmill (n = 13), cycle (n = 15), or control group (n = 14). Treadmill and cycle groups trained three times a week for 6 weeks, whereas the control group did not train during this period. Maximal and pain-free exercise times were measured on graded treadmill and cycle tests before and after training. Results. Treadmill training significantly improved maximal and pain-free treadmill walking times but did not improve cycle performance. Cycle training significantly improved maximal cycle time but did not improve treadmill performance. However, there was evidence of a stronger cross-transfer effect between the training modes for patients who reported a common limiting symptom during cycling and walking at baseline. There was also considerable variation in the training response to cycling, and a subgroup of responsive patients in the cycle group improved their walking performance by more than the average response observed in the treadmill group. Conclusion: These findings suggest that cycle exercise is not effective in improving walking performance in all claudication patients but might be an effective alternative to walking in those who exhibit similar limiting symptoms during both types of exercise.

Cardiac contributions to exercise training responses in patients with chronic heart failure: A strain imaging study

The improvement of exercise capacity due to exercise training in heart failure has been associated with peripheral adaptation, but the contribution of cardiac responses is less clear. We sought the extent to which the improvement of functional capacity in patients undergoing exercise training for heart failure was related to myocardial performance. Thirty-seven patients (35 men, age 64 +/- 11) with symptomatic heart failure and left ventricular ejection fraction

Acute weight loss followed by an aggressive nutritional recovery strategy has little impact on on-water rowing performance

Objectives: To assess the influence of moderate, acute weight loss on on-water rowing performance when aggressive nutritional recovery strategies were used in the two hours between weigh in and racing. Methods: Competitive rowers (n=17) undertook three on-water 1800 m time trials under cool conditions ( mean (SD) temperature 8.4 (2.0)degrees C), each separated by 48 hours. No weight limit was imposed for the first time trial-that is, unrestricted body mass (UNR1). However, one of the remaining two trials followed a 4% loss in body mass in the previous 24 hours (WT-4%). No weight limit was imposed for the other trial (UNR2). Aggressive nutritional recovery strategies (WT-4%, 2.3 g/kg carbohydrate, 34 mg/kg Na+, and 28.4 ml/kg fluid; UNR, ad libitum) were used in the first 90 minutes of the two hours between weigh in and performance trials. Results: WT-4% had only a small and statistically non-significant effect on the on-water time trial performance ( mean 1.0 second, 95% confidence interval (CI) 20.9 to 2.8; p=0.29) compared with UNR. This was despite a significant decrease in plasma volume at the time of weigh in for WT-4% compared with UNR (-9.2%, 95% CI -12.8% to -5.6%; p

Muscle metabolism during constant- and alternating-intensity exercise around critical power

Few studies have focused on the metabolic responses to alternating high- and low-intensity exercise and, specifically, compared these responses to those seen during constant-load exercise performed at the same average power output. This study compared muscle metabolic responses between two patterns of exercise during which the intensity was either constant and just below critical power (CP) or that oscillated above and below CP. Six trained males (mean +/- SD age 23.6 +/- 2.6 y) completed two 30-minute bouts of cycling (alternating and constant) at an average intensity equal to 90% of CR The intensity during alternating exercise varied between 158% CP and 73% CP. Biopsy samples from the vastus lateralis muscle were taken before (PRE), at the midpoint and end (POST) of exercise and analysed for glycogen, lactate, PCr and pH. Although these metabolic variables in muscle changed significantly during both patterns of exercise, there were no significant differences (p > 0.05) between constant and alternating exercise for glycogen (PRE: 418.8 +/- 85 vs. 444.3 +/- 70; POST: 220.5 +/- 59 vs. 259.5 +/- 126mmol.kg(-1) dw), lactate (PRE: 8.5 +/- 7.7 vs. 8.5 +/- 8.3; POST: 49.9 +/- 19.0 vs. 42.6 +/- 26.6 mmol.kg(-1)dw), phosphocreatine (PRE: 77.9 +/- 11.6 vs. 75.7 +/- 16.9; POST: 65.8 +/- 12.1 vs. 61.2 +/- 12.7mmol.kg(-1)dw) or pH (PRE: 6.99 +/- 0.12 vs. 6.99 +/- 0.08; POST: 6.86 +/- 0.13 vs. 6.85 +/- 0.06), respectively. There were also no significant differences in blood lactate responses to the two patterns of exercise. These data suggest that, when the average power output is similar, large variations in exercise intensity exert no significant effect on muscle metabolism.

Relationships between quality of experience and participation in diverse performance settingshttp://espace.library.uq.edu.au/workflow/edit_metadata.php?id=382160&wfs_id=778

The flow concept describes a model of enjoyment that has relevance for understanding participation and experience across a wide range of activities (Csikszentmihalyi, 1997). The basic premise of the flow concept is that when challenges and skills are simultaneously balanced and extending the individual, a state of total absorption can occur. Research by Jackson and colleagues has examined the utility of the flow concept to understanding participation and performance in sport settings. Recently, Jackson and Eklund have examined flow in a range of performance settings: sport, exercise, dance, creative and performing arts, and music. In this paper, we present descriptive and construct validity data on how participants in these activities experienced flow, as assessed by the recently revised flow scales: The Dispositional Flow Scale-2 (DFS-2) and Flow State Scale-2 (FSS-2) (Jackson & Eklund, 2002). The fmdings will be discussed in relation to the utility of the flow concept to understanding participation across performance settings.

High- and low-volume resistance training similarly enhances functional performance in older adults

It is well known that resistance training improves muscle strength in older adults and may enhance or preserve functional performance. However, it is unclear if the volume of work undertaken in the elderly alters the response in functional performance. PURPOSE: To investigate the effect of a high- versus low-volume resistance training program on functional performance in older adults. METHODS: Thirty-two healthy men and women aged 65-78 years were randomly assigned to either a single-set (SS, n = 16) or 3-set (MS, n = 16) progressive resistance training program for 20 weeks. Groups trained 2 days per week using machine weights at 8 repetitions maximum (8-RM) for 7 upper and lower body exercises. Muscle strength was assessed by the 1-RM and functional performance by a battery of tests (repeated chair rise, usual and fast 6-m walk, 6-m backwards walk, floor rise to standing, stair climb, and 400-m walk time). RESULTS: Twenty-eight subjects completed the study. There was no difference between groups at baseline in muscle strength or functional performance. Whole body muscle strength significantly increased in both groups with greater gains in the 3-set group (MS 32.9 ± 3.1%; SS 18.6 ± 2.7%, mean ± SE; P < 0.01). Significant improvement (time effect, P < 0.01) occurred for both groups in the chair rise (MS 13.6 ± 3.2%; SS 10.2 ± 3.0%), 6-m backwards walk (MS 14.9 ± 3.3%; SS 14.3 ± 4.2%), stair climb (MS 6.4 ± 2.8%; SS 7.7 ± 3.1%) and 400-m walk (MS 7.4 ± 1.4%; SS 3.9 ± 1.2%). There were no interaction (group × time) effects for functional performance and no differences by sex. CONCLUSION: Resistance training that utilizes either a singleset or 3-set regimen may significantly and similarly improve functional performance in community-dwelling older adults. Enhancement of functional performance may prolong independence and improve quality of life. ©2004The American College of Sports Medicine