Exercise Physiology

PURPOSE: The present longitudinal study assessed cardiorespiratory capacity and running economy of Olympic athletes over several decades to measure changes in fitness in an elite group during aging. METHODS: Twenty-six male runners training for the 1968 Olympics were recruited. HR, V˙O2max, ventilation, and running economy were measured in 1968, 1993, and 2013. In 2013, 22 of the original runners participated: three passed away between 1993 and 2013 and one declined to participate...

In this study we tested the hypothesis that inspiring a low-density gas mixture (helium-oxygen; HeO2) would minimize mechanical ventilatory constraints and preferentially increase exercise performance in females relative to males. Trained male (n = 11, 31 yr) and female (n = 10, 26 yr) cyclists performed an incremental cycle test to exhaustion to determine maximal aerobic capacity (V̇o2max; male = 61, female = 56 ml·kg(-1)·min(-1)). A randomized, single-blinded crossover design was used for two experimental days where subjects completed a 5-km cycling time trial breathing humidified compressed room air or HeO2 (21% O2:balance He)...

The primary aim of this study was to develop statistical models to predict peak oxygen consumption (VO2 peak) using OMNI Ratings of Perceived Exertion measured during submaximal cycle ergometry. Male (M = 20.9 yr., SE = 0.4) and female (M = 21.6 yr., SE = 0.5) participants (N = 81) completed a load-incremented maximal cycle ergometer exercise test. Simultaneous multiple linear regression was used to develop separate VO2 peak statistical models using submaximal ratings of perceived exertion for the overall body, legs, and chest/breathing as predictor variables...

In this study we aimed to establish the usefulness of the time constant of heart rate recovery (Tr) in the evaluation of cardiovascular fitness. 15 male subjects exercised on recumbent bicycle at three different workloads (75 W, 100 W 125 W) where R-R intervals were monitored to determine Tr. In order to find the maximal oxygen uptake (VdotO2max) of each subject, oxygen consumption rate (VdotO2max) was recorded throughout the treadmill exercise (10 km/h). Based on VdotO2max, we classified the subjects into two groups: the "fit" group and the "unfit" group...

BACKGROUND: Prior research has found affect to predict exercise. Little research has examined the causal influence of exercise-related affect on exercise intentions. PURPOSE: The purpose of this study was to test whether expectations about post-exercise affect can be successfully manipulated to produce changes in post-exercise affect and exercise intentions. We also tested whether cognitively elaborating on the expectation would increase the duration of the expectation effect...

BACKGROUND: Heart rate reserve (HRR) has been reported to be inversely associated with cardiovascular (CV) disease and death. The impact of physical fitness (PF) on this relationship has not, however, been described in detail. We investigated how different levels of PF influenced the association between HRR and CV death during a 35-year follow-up. METHODS AND RESULTS: HRR and PF were measured in 2014 apparently healthy, middle-aged men during a symptom-limited bicycle exercise test in 1972-75...

PURPOSE: To assess the validity of methods for quantifying training load, fitness and fatigue in endurance athletes using a mathematical model. METHODS: Seven trained runners (VO2max: 51.7 ± 4.5 mL kg(-1) min(-1), age: 38.6 ± 9.4 years, mean ± SD) completed 15 weeks of endurance running training. Training sessions were assessed using a heart rate (HR), running pace and rating of perceived exertion (RPE). Training dose was calculated using the session-RPE method, Banisters TRIMP and the running training stress score (rTSS)...

We investigated the influence of hypoxia on the asymptote (critical power, CP) and the curvature constant (W') of the hyperbolic power-duration relationship, as measured by both conventional and all-out testing procedures. 13 females completed 5 constant-power prediction trials and a 3-min all-out test to estimate CP and W', in both normoxia (N) and moderate hypoxia (H; FiO2=0.13). CP was significantly reduced in hypoxia compared to normoxia when estimated by conventional (H:132±17 vs. N:175±25 W; P<0...

To decelerate the body and limbs, muscles lengthen actively to dissipate energy. During rapid energy-dissipating events, tendons buffer the work done on muscle by storing elastic energy temporarily, then releasing this energy to do work on the muscle. This elastic mechanism may reduce the risk of muscle damage by reducing peak forces and lengthening rates of active muscle.

PURPOSE: While the lack of muscular activity is a proposed trigger for metabolic alterations, this association has not been directly measured. We examined the associations between EMG-derived muscle inactivity and activity patterns and cardiometabolic biomarkers in healthy, physically active adults. METHODS: Data for this cross-sectional study were pooled from two studies (EMG24 and InPact), resulting in a sample of 150 individuals without known chronic diseases and with high-quality EMG data (female n = 85, male n = 65, age = 38...

PURPOSE: This study aimed to investigate the influence of localized muscle cooling on postexercise vascular, metabolic, and mitochondrial-related gene expression. METHODS: Nine physically active males performed 30 min of continuous running at 70% of their maximal aerobic velocity, followed by intermittent running to exhaustion at 100% maximal aerobic velocity. After exercise, subjects immersed one leg in a cold water bath (10°C, COLD) to the level of their gluteal fold for 15 min...

Many locomotor activities require muscles to actively lengthen, dissipate energy and decelerate the body. These eccentric contractions can disrupt cytoskeletal structures within myofibrils and reduce force output. We examined how architectural features of pennate muscles can provide a protective mechanism against eccentric muscle damage by limiting fascicle lengthening. It has been previously shown that the angled fibers of pennate muscles change orientation when shortening. This change in fiber orientation can amplify fascicle shortening, resulting in a velocity advantage at the level of the muscle-tendon unit (MTU) that is characterized by a gear ratio (MTU velocity/fascicle velocity)...

Anaerobic capacity/anaerobically attributable power is an important parameter for athletic performance, not only for short high-intensity activities but also for breakaway efforts and end spurts during endurance events. Unlike aerobic capacity, anaerobic capacity cannot be easily quantified. The 3 most commonly used methodologies to quantify anaerobic capacity are the maximal accumulated oxygen deficit method, the critical power concept, and the gross efficiency method. This review describes these methods, evaluates if they result in similar estimates of anaerobic capacity, and highlights how anaerobic capacity is used during sporting activities...