Physiological Adaptations to Hypoxic vs. Normoxic Training during Intermittent Living High.

In the setting of "living high," it is unclear whether high-intensity interval training (HIIT) should be performed "low" or "high" to stimulate muscular and performance adaptations. Therefore, 10 physically active males participated in a 5-week "live high-train low or high" program (TR), whilst eight subjects were not engaged in any altitude or training intervention (CON). Five days per week (~15.

History-dependent force, angular velocity and muscular endurance in ACTN3 genotypes.

Purpose: This study aimed at determining the influence of the ACTN3 R577X polymorphism on muscle strength and muscle endurance in non-athletic young men.

Methods: 266 healthy young men were included in this study. Each subject performed maximal isometric, concentric and eccentric contractions of the knee extensor muscles on an isokinetic dynamometer.

Force depression and relaxation kinetics after active shortening and deactivation in mouse soleus muscle.

After active shortening, isometric force production capacity of muscle is reduced (force depression, FD). The mechanism is incompletely understood but increasing cross-bridge detachment and/or decreasing attachment rate might be involved. Therefore we aimed to investigate the relation between work delivered during shortening (W), and change in half-relaxation time (Δ0.