Validity and reliability of the single-trial line drill test of anaerobic power in basketball players.

AIM: This study evaluated the validity, reliability, and sensitivity of the single-trial line drill test (SLDT) for anaerobic power assessment. METHODS: Twenty-four volunteers were assigned to either a control (C, N.=12) or an experimental (BP, N.=12 basketball players) group. SLDT's (time-to-complete) concurrent validity was evaluated against the Wingate testing (WAnT: mean [MP] and peak power [PP]) and a 30-sec vertical jump testing test (VJT: mean height and MP). Blood lactate concentration was measured at rest and immediately post-test. SLDT's reliability [test-retest intraclass correlation coefficients (ICC), coefficient of variation (CV), Bland-Altman plots] and sensitivity were determined (one-way ANOVA). RESULTS: Kendall's tau correlation analysis revealed correlations (P<0.05) between SLDT time and WAnT's PP (=0.78) and MP (=0.56) and VJT's MP (=0.85) and height (=0.90). SLDT lactate concentration was moderately (P<0.05) correlated with the respective lactate values of WAnT (=0.40) and VJT (=0.66). SLDT time in BP correlated (P<0.05) with VJT's MP (=0.80) and height (=0.90) but not with WAnT performance variables. SLDT lactate responses in BP were moderately (P<0.05) correlated with WAnT's PP (=0.54) and VJT MP (=0.68), height (=0.65), and lactate concentration (=0.65). ICCs for time and lactate were 0.92 and 0.93, respectively (P<0.05) although Bland-Altman plots and CV indicate that SLDT time demonstrated greater reliability than lactate responses. In all tests, BP demonstrated higher (P<0.05) performance levels compared to C indicating an adequate sensitivity for SLDT. CONCLUSION: Results suggest that the SLDT appears to be a valid, reliable, and sensitive field test of anaerobic capacity for basketball players.

Effect of rhythmic gymnastics on volumetric bone mineral density and bone geometry in premenarcheal female athletes and controls.

CONTEXT AND OBJECTIVE: Weight-bearing exercise during growth exerts positive effects on the skeleton. Our objective was to test the hypothesis that long-term elite rhythmic gymnastics exerts positive effects on volumetric bone mineral density and geometry and to determine whether exercise-induced bone adaptation is associated with increased periosteal bone formation or medullary contraction using tibial peripheral quantitative computed tomography and bone turnover markers. DESIGN AND SETTING: We conducted a cross-sectional study at a tertiary center. SUBJECTS: We studied 26 elite premenarcheal female rhythmic gymnasts (RG) and 23 female controls, aged 9-13 yr. MAIN OUTCOME MEASURES: We measured bone age, volumetric bone mineral density, bone mineral content (BMC), cortical thickness, cortical and trabecular area, and polar stress strength index (SSIp) by peripheral quantitative computed tomography of the left tibia proximal to the distal metaphysis (trabecular) at 14, 38 (cortical), and 66% (muscle mass) from the distal end and bone turnover markers. RESULTS: The two groups were comparable according to height and chronological and bone age. After weight adjustment, cortical BMC, area, and thickness at 38% were significantly higher in RG (P < 0.005-0.001). Periosteal circumference, SSIp, and muscle area were higher in RG (P < 0.01-0.001). Muscle area was significantly associated with cortical BMC, area, and SSIp, whereas years of training showed positive association with cortical BMC, area, and thickness independent of chronological age. CONCLUSIONS: RG in premenarcheal girls may induce positive adaptations on the skeleton, especially in cortical bone. Increased duration of exercise is associated with a positive response of bone geometry.

Strength training and detraining effects on muscular strength, anaerobic power, and mobility of inactive older men are intensity dependent.

BACKGROUND: Although strength training (ST) enhances physical function in the elderly, little is known about the effect of training intensity on training and detraining adaptations in musculoskeletal fitness. OBJECTIVE: To determine the effect of exercise intensity on strength, anaerobic power, and mobility of older men subjected to a 24 week ST protocol followed by prolonged detraining. METHODS: Fifty two healthy but inactive older men (mean (SD) age 71.2 (4.1) years) were assigned to a control (n = 14), low intensity training (LIST; n = 18; 55% 1RM), or high intensity training (HIST; n = 20; 82% 1RM) group. They carried out a 24 week, whole body (10 exercises, two to three sets/exercise) ST programme followed by a 48 week detraining period. Upper and lower body strength, anaerobic power (Wingate testing), and mobility (timed up and go, walking, climbing stairs) were measured at baseline and immediately after training and during detraining. RESULTS: Although low intensity training improved (p<0.05) strength (42-66%), anaerobic power (10%), and mobility (5-7%), high intensity training elicited greater (p<0.05) gains (63-91% in strength, 17-25% in anaerobic power, 9-14% in mobility). All training induced gains in the LIST group had been abolished after four to eight months of detraining, whereas in the HIST group strength and mobility gains were maintained throughout detraining. However, anaerobic power had returned to baseline levels after four months of detraining in both groups. CONCLUSIONS: Higher intensity training protocols induce greater gains in strength, anaerobic power, and whole body physical function of older men. Moreover, higher intensity training may maintain the gains for more prolonged periods after training ceases.

Leptin and adiponectin responses in overweight inactive elderly following resistance training and detraining are intensity related.

CONTEXT: Adiponectin and leptin are closely related to weight control and energy balance, whereas exercise affects elderly metabolic regulation and functional capacity. OBJECTIVE: The objective of this study was to investigate leptin and adiponectin responses in elderly males after exercise training and detraining. DESIGN: The study design was a 1-yr randomized controlled trial. SETTING: The study was performed at the Laboratory of Physical Education and Sport Science Department. PARTICIPANTS: Fifty inactive men [age, 65-78 yr; body mass index (BMI), 28.7-30.2 kg/m2] were recruited from a volunteer database by word of mouth and fliers sent to medical practitioners, physiotherapists, and nursing homes in the local community. INTERVENTION(S): Participants were randomly assigned to a control (n = 10), low-intensity (n = 14), moderate-intensity (n = 12), or high-intensity training (HI; n = 14) group. Resistance training (6 months, 3 d/wk, 10 exercises/three sets) was followed by 6 months of detraining. MAIN OUTCOME MEASURE(S): Strength, exercise energy cost, skinfold sum, body weight, maximal oxygen consumption, resting metabolic rate (RMR), and plasma leptin and adiponectin were determined at baseline and after training and detraining. RESULTS: Strength, maximal oxygen consumption, RMR, and exercise energy cost increased (P < 0.05) after training in an intensity-dependent manner. Skinfold sum and BMI were reduced by resistance training (P < 0.05), with HI being more effective (P < 0.05) than moderate-intensity/low-intensity training. Leptin was diminished (P < 0.05) by all treatments, whereas adiponectin increased (P < 0.05) only in HI. Detraining maintained training-induced changes only in HI. The percent leptin decrease was associated (P < 0.05) with the percent BMI decrease and the percent RMR increase, whereas the percent adiponectin increase was associated (P < 0.05) with the percent BMI decrease. CONCLUSIONS: Resistance training and detraining may alter leptin and adiponectin responses in an intensity-dependent manner. Leptin and adiponectin changes were strongly associated with RMR and anthropometric changes.