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Exercise load is a key component in determining end-point adaptations to resistance exercise. Yet, there is no information regarding the use of different inertia (i.e., loads) during isoinertial flywheel resistance exercise, a very popular high-intensity training model. Thus, this study examined power, work, force, and eccentric overload produced during flywheel resistance exercise with different inertial settings in men and women. Twenty-two women (n = 11) and men (n = 11) performed unilateral (in both legs) isolated concentric (CON) and coupled CON and eccentric (ECC) exercise in a flywheel knee extension device employing 6 inertias (0.0125, 0.025, 0.0375, 0.05, 0.075, 0.1 kg⋅m-2). Power decreased as higher inertias were used, with men showing greater (p ≤ 0.05) decrements than women (-36 vs. -29% from lowest to highest inertia). In contrast, work increased as higher inertias were employed, independent of sex (p ≤ 0.05; ~48% from lowest to highest inertia). Women increased CON and ECC mean force (46-55%, respectively) more (p ≤ 0.05) than men (34-50%, respectively) from the lowest to the highest inertia evaluated, although the opposite was found for peak force data (i.e., peak force increased more in men than in women as inertia was increased). Men, but not women, increased ECC overload from inertia 0.0125 to 0.0375 kg⋅m². Although estimated stretch-shorting cycle use during flywheel exercise was higher (p ≤ 0.05) in men (6.6%) than women (4.9%), values were greater for both sexes when using low-to-medium inertias. The information gained in this study could help athletes and sport and health professionals to better understand the impact of different inertial settings on skeletal muscle responses to flywheel resistance exercise. [ABSTRACT FROM AUTHOR]

This study examined the effects of a high-speed power training program in peak muscle power and maximal voluntary isometric contraction (MVIC) of knee extensors in patients with relapsing-remitting multiple sclerosis (MS). Forty patients, 20 women (age 42.8 +/- 10.3 yr) and 20 men (age 44.0 +/- 8.7 yr) diagnosed with relapsing-remitting MS were randomly assigned, with respect to sex, to either an exercise group or a control group. Participants from the exercise group performed 12 wk of supervised muscle power training of knee extensors. All subjects were tested for MVIC and peak muscle power at baseline and after the training intervention. A strain gauge was used to measure the MVIC, and peak muscle power was assessed with a linear encoder at five relative loads. The training-related effects were assessed using a t-test. The results showed no significant changes in the control group from baseline to postintervention evaluation. In contrast, the exercise group significantly increased MVIC (10.8%; p < 0.05) and muscle power at 40, 50, 60, 70, and 80% of the MVIC by 21.8, 14.5, 17.3, 19.4, and 22.3%, respectively (p < 0.01), after the training. These findings suggest that 12 wk of high-speed power training improve both MVIC and muscle power at five different loads in patients with relapsing-remitting MS. [ABSTRACT FROM AUTHOR]

BACKGROUND: Although resistance training adaptations in multiple sclerosis (MS) patients have been described, the detraining response in this population is largely unknown. OBJETIVE: This study was designed to evaluate the effects of a 12-week detraining period on muscle strength (isometric and endurance) and muscle power of multiple sclerosis (MS) patients that had previously carried out a 12-week resistance training program (RTP). METHODS: Forty-two MS patients were randomly assigned into two groups: an exercise group (EG) that performed a 12-week RTP for the knee extensors muscles; and a control group (CG), that did not perform any specific training. Knee extension maximal voluntary isometric contraction (MVIC), muscle power and muscle endurance were evaluated before and after the RTP, as well as 12 weeks after training completion. A strain gauge was used to measure the maximal voluntary isometric contraction and muscle power was assessed with a linear encoder. Muscle endurance was interpreted as the number of repetitions that a patient could perform in a single set of knee extension exercise. RESULTS: The EG increased MVIC and muscle power after the training period, although the training did not affect muscle endurance. After 12 weeks of detraining, MVIC returned to pre-training values but muscle power was still greater than pre-training values in the EG. The CG did not present any change in the variables measured during the intervention. CONCLUSIONS: A 12-week RTP improved MVIC and muscle power in MS patients. Additionally, 12 weeks of detraining blunted strength training adaptations in MS patients, although muscle power training adaptations were still evident after the detraining period. [ABSTRACT FROM AUTHOR]

The article reports on research which was conducted to investigate the impact that an acute aerobic exercise session had on molecular responses to subsequent resistance exercises. Researchers evaluated nine physically active men who performed a 45 minute one legged cycle ergometry exercise and knee extensions for each leg which were performed six hours later. They found that acute aerobic exercise altered molecular events regulating muscle protein turnover during the early recovery period from subsequent resistance exercise.

Objectives: The aim of the study were to (1) investigate what physical and physiological parameters are most important for Frame Running capacity, a parasport for individuals with ambulatory difficulties, and (2) determine whether Frame Running capacity can be predicted in athletes with cerebral palsy. Design: Athletes with cerebral palsy (N = 62, Gross Motor Classification System I–V; 2/26/11/21/2) completed a 6-min Frame Running test. Before the 6-min Frame Running test, muscle thickness, passive range of motion (hip, knee, ankle), selective motor control, and spasticity (hip, knee, ankle) were measured in both legs. In total, 54 variables per individual were included. Data were analyzed using correlations, principal component analysis, orthogonal partial least square regression, and variable importance in projection analysis. Results: The mean 6-min Frame Running test distance was 789 ± 335 m and decreased with motor function severity. The orthogonal partial least square analysis revealed a modest degree of covariance in the variables analyzed and that the variance in the 6-min Frame Running test distance could be predicted with 75% accuracy based on all the variables measured. Variable importance in projection analysis indicated hip and knee extensor spasticity (negative effect), and muscle thickness (positive effect) arose as the most important factors contributing to Frame Running capacity. Conclusions: These results are an important resource to enable optimization of training regimes to improve Frame Running capacity and contribute to evidence-based and fair classification for this parasport. [ABSTRACT FROM AUTHOR]