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KEY POINTS: The power-asymptote (critical power; CP) of the hyperbolic power-time relationship for high-intensity exercise defines a threshold between steady-state and non-steady-state exercise intensities and the curvature constant (W') indicates a fixed capacity for work >CP that is related to a loss of muscular efficiency. The present study reports novel evidence on the muscle metabolic underpinnings of CP and W' during whole-body exercise and their relationships to muscle fibre type. We show that the W' is not correlated with muscle fibre type distribution and that it represents an elevated energy contribution from both oxidative and glycolytic/glycogenolytic metabolism. We show that there is a positive correlation between CP and highly oxidative type I muscle fibres and that muscle metabolic steady-state is attainable CP. Our findings indicate a mechanistic link between the bioenergetic characteristics of muscle fibre types and the power-time relationship for high-intensity exercise.ABSTRACT: We hypothesized that: (1) the critical power (CP) will represent a boundary separating steady-state from non-steady-state muscle metabolic responses during whole-body exercise and (2) that the CP and the curvature constant (W') of the power-time relationship for high-intensity exercise will be correlated with type I and type IIx muscle fibre distributions, respectively. Four men and four women performed a 3 min all-out cycling test for the estimation of CP and constant work rate (CWR) tests slightly >CP until exhaustion (Tlim ), slightly CP Tlim isotime to test the first hypothesis. Eleven men performed 3 min all-out tests and donated muscle biopsies to test the second hypothesis. Below CP, muscle [PCr] [42.6 ± 7.1 vs. 49.4 ± 6.9 mmol (kg d.w.)(-1) ], [La(-) ] [34.8 ± 12.6 vs. 35.5 ± 13.2 mmol (kg d.w.)(-1) ] and pH (7.11 ± 0.08 vs. 7.10 ± 0.11) remained stable between ∼12 and 24 min (P > 0.05 for all), whereas these variables changed with time >CP such that they were greater [[La(-) ] 95.6 ± 14.1 mmol (kg d.w.)(-1) ] and lower [[PCr] 24.2 ± 3.9 mmol (kg d.w.)(-1) ; pH 6.84 ± 0.06] (P < 0.05) at Tlim (740 ± 186 s) than during the

This study examined the effect of recreational football and resistance training on bone mineral density (BMD) and bone turnover markers (BTMs) in elderly men. Twenty-six healthy sedentary men (age 68.2 ± 3.2 years) were randomized into three groups: football (F; n = 9) and resistance training (R; n = 9), completing 45-60 min training two to three times weekly, and inactive controls (C; n = 8). Before, after 4 months, and after 12 months, BMD in proximal femur (PF) and whole body (WB) were determined together with plasma osteocalcin (OC), procollagen type-1 amino-terminal propeptide (P1NP), and carboxy-terminal type-1 collagen crosslinks (CTX-1). In F, BMD in PF increased up to 1.8% (P < 0.05) from 0 to 4 months and up to 5.4% (P < 0.001) from 0 to 12 months; WB-BMD remained unchanged. After 4 and 12 months of football, OC was 45% and 46% higher (P < 0.001), and P1NP was 41% and 40% higher (P < 0.001) than at baseline, respectively. After 12 months, CTX-1 showed a main effect of 43% (P < 0.05). In R and C, BMD and BTM remained unchanged. In conclusion, 4 months of recreational football for elderly men had an osteogenic effect, which was further developed after 12 months, whereas resistance training had no effect. The anabolic response may be due to increased bone turnover, especially improved bone formation.

The study examined the effects of 1 year of football or strength training on cardiovascular function in 65- to 75-year-old men. Twenty-six untrained men (age: 68.2 ± 3.2 years) were randomized to football training (FTG; n = 9), strength training (STG; n = 9), or control (CG; n = 8). In FTG, left ventricular (LV) internal diastolic diameter, end-diastolic volume, and mass index were 8%, 21%, and 18% higher (P < 0.01), respectively, after 12 months, with no changes in STG and CG. After 12 months, LV ejection fraction was increased (P < 0.05) by 8% and 5% in FTG and STG, respectively, and systolic longitudinal two-dimensional strain by 8% and 6%, whereas right ventricular systolic function improved (P < 0.05) by 22% in FTG, but not in STG and CG. In FTG, LV diastolic mitral inflow (E/A) ratio and peak early diastolic velocity (E') improved (P < 0.05) by 25% and 12%, respectively, after 12 months, with no changes in STG and CG. In FTG, maximum oxygen uptake was 16% and 18% higher (P < 0.001) after 4 and 12 months, respectively, and resting heart rate was 6 and 8 beats per minute lower (P < 0.001), respectively, with no changes in STG and CG. In conclusion, football training elicited superior cardiovascular effects compared with strength training in elderly untrained men.

Androgen deprivation therapy (ADT) remains a cornerstone in the management of patients with prostate cancer (PCa) despite adverse effects on body composition and functional parameters. We compared the effects of football training with standard care in PCa patients managed with ADT (>6 months). Fifty-seven men aged 67 (range: 43-74) were randomly assigned to a football group (FG, n=29) or a usual care control group (CON, n=28). The primary outcome was change in lean body mass (LBM) assessed by dual-energy X-ray absorptiometry scanning. Secondary outcomes included changes in knee-extensor muscle strength (one repetition maximum), fat percentage, and maximal oxygen uptake (VO 2max). Mean heart rate during training was 137.7 (standard deviation 13.7) bpm or 84.6 (3.9)% HRmax. In FG, LBM increased by 0.5kg [95% confidence interval (CI) 0.1-0.9; P=0.02] with no change in CON (mean group difference 0.7kg; 95% CI 0.1-1.2; P=0.02). Also, muscle strength increased in FG (8.9kg; 95% CI 6.0-11.8; P2max increased (1.0mL/kg/min; 95% CI 0.2-1.9; P=0.02) and fat percentage tended to decrease (0.7%; 95%CI 1.3-0.0; P=0.06), but these changes were not significantly different from CON. In conclusion, football training over 12 weeks improved LBM and muscle strength compared with usual care in men with prostate cancer receiving ADT.