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.

Resistance training effects on muscular strength of elderly are related to intensity and gender.

The purpose of this study was to determine whether a high intensity (HI) versus a moderate (MI) or low-intensity (LI) training program would be more effective in improving the isokinetic knee extension muscular performance in healthy inactive men and women. Sixty-four participants, men and women, were randomly assigned to one of four groups: control group (C), LI (50% of 1RM), the MI group (70% of 1RM) and the HI (90% of 1RM). Participants exercised on three resistance exercise machines: leg extension, leg curls and leg press. The isokinetic testing method (concentric mode) applied prior to and at the end of the training period (16 weeks, three 3 times per week) to assess the knee muscular performance. MANOVA repeated measures revealed that the HI group demonstrated the most strength gains following a speed specificity pattern (most considerable improvement occurred at or near slow speeds from 7.3% to 11.2% for male and from 2.3% to 15.2% for female). In addition, males demonstrated a greater improvement of knee extension power output than females. In conclusion, HI strength training is proposed for elderly men and women as the most effective protocol. Furthermore only at low-velocity testing, women of the HI showed a greater change than men (p < 0.05). Regarding strength increase in relation to various testing velocities, a greater increase was found in HI at low velocities, with the other training groups exhibiting almost similar strength increase at all tested speeds.

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.

The effects of strength training, cardiovascular training and their combination on flexibility of inactive older adults.

The purpose of this study was to investigate the effects of aerobic training, strength training and their combination on joint range of motion of inactive older individuals. Thirty-two inactive older men (65 - 78 yr) were assigned to one of four groups (n = 8 per group): control (C), strength training (ST), cardiovascular training (CT), and combination of strength and aerobic training (SA). Subjects in the S, A, and SA trained three times a week for 16 weeks. ST included 10 resistance exercises for the major muscle groups at an intensity of 55 - 80% of 1-RM and CT included walking/jogging at 50 - 80 % of maximal heart rate. Body weight and height, physical activity level and maximal oxygen uptake (.VO(2)max) were measured before the training period. Isokinetic (60 and 180 deg x sec(-1)) and concentric strength (1-RM in bench and leg press) were assessed prior to and at the end of the training period. Hip flexion, extension, abduction, and adduction, shoulder extension, flexion, and adduction, knee flexion, elbow flexion and sit-and-reach score were determined before and at 8 and 16 weeks of training. There were no differences between groups in .VO(2)max, body weight, and height (p < 0.05). ST and SA but not CT and C increased isokinetic and concentric strength at the end of the training period (p < 0.05). ST and SA increased significantly (p < 0.05) sit-and-reach performance, elbow flexion, knee flexion, shoulder flexion and extension and hip flexion and extension both at mid- and post-training. CT increased (p < 0.05) only hip flexion and extension at post training. Results indicate that resistance training may be able to increase range of motion of a number of joints of inactive older individuals possibly due to an improvement in muscle strength.