Breathing valve resistance alters physiological responses during a graded exercise test.

Purpose: To determine the impact of breathing valve resistance on peak aerobic capacity ([Formula: see text]) and running economy (RE) in endurance-trained and recreationally active individuals.

Methods: Ten endurance-trained males (ETM), 10 endurance-trained females (ETF), 10 recreationally active males (RAM), and 10 recreationally active females (RAF) participated in this study. On two separate occasions, subjects performed identical graded exercise treadmill protocols using either a Hans Rudolph 2700 (high resistance) or a Daniels' (low resistance) two-way non-rebreathing valve.

Beneficial Effects of Cooling during Constant Power Non-steady State Cycling.

This study compared the effects of cooling on the energetic and associated physiological and perceptual responses to constant power, non-steady state cycling. Twelve males cycled at their lactate threshold power for 60 min or until exhaustion under 3 conditions: wearing a cooling vest and sleeves (COOL), a synthetic shirt embedded with an active particle technology claimed to facilitate evaporative heat loss (EVAP), and a standard synthetic shirt (CON). When adjusted for time, the increase in gastrointestinal temperature from baseline was reduced during COOL and EVAP compared to CON (1.

Measuring changes in aerodynamic/rolling resistances by cycle-mounted power meters.

Purpose: To develop a protocol for isolating changes in aerodynamic and rolling resistances from field-based measures of power and velocity during level bicycling.

Methods: We assessed the effect of body position (hands on brake hoods vs drops) and tire pressure changes (414 vs 828 kPa) on aerodynamic and rolling resistances by measuring the power (Pext)-versus-speed (V) relationship using commercially available bicycle-mounted power meters. Measurements were obtained using standard road bicycles in calm wind (<1.