Search Results

You are looking at 71 - 80 of 388 items for :

  • "physiologic responses" x
Clear All
Restricted access

Thomas Rowland

Interest in the physiological responses to exercise unique to the pediatric age group has grown exponentially over the past 50 years. A number of issues surrounding children’s exercise have been particularly responsible for this trend, particularly a) recognition of the health benefits of exercise in youth, b) the growing involvement of young persons in highly intense levels of sports play, and c) the role that exercise may play in the diagnosis and management of children with chronic disease. As a consequence, current research to date has provided a comprehensive picture of the features specific to children’s response to exercise. Future challenges facing the field of pediatric exercise science involve translating this information into practical guidelines which can be applied to the realms of clinical medical practice, preventive health initiatives, and athletic training regimens which are appropriate for this age group.

Restricted access

William M. Bertucci, Andrew C. Betik, Sebastien Duc and Frederic Grappe

This study was designed to examine the biomechanical and physiological responses between cycling on the Axiom stationary ergometer (Axiom, Elite, Fontaniva, Italy) vs. field conditions for both uphill and level ground cycling. Nine cyclists performed cycling bouts in the laboratory on an Axiom stationary ergometer and on their personal road bikes in actual road cycling conditions in the field with three pedaling cadences during uphill and level cycling. Gross efficiency and cycling economy were lower (–10%) for the Axiom stationary ergometer compared with the field. The preferred pedaling cadence was higher for the Axiom stationary ergometer conditions compared with the field conditions only for uphill cycling. Our data suggests that simulated cycling using the Axiom stationary ergometer differs from actual cycling in the field. These results should be taken into account notably for improving the precision of the model of cycling performance, and when it is necessary to compare two cycling test conditions (field/laboratory, using different ergometers).

Restricted access

Jerry Mayo, Brian Lyons, Kendal Honea, John Alvarez and Richard Byrum

Context:

Rehabilitation specialists should understand cardiovascular responses to different movement patterns.

Objective:

To investigate physiological responses to forward- (FM), backward- (BM), and lateral-motion (LM) exercise at self-selected intensities.

Design:

Within-subjects design to test independent variable, movement pattern; repeated-measures ANOVA to analyze oxygen consumption (VO2), heart rate (HR), respiratory-exchange ratio (RER), and ratings of perceived exertion (RPE).

Participants:

10 healthy women.

Results:

VO2 and HR were significantly higher during LM than during FM and BM exercise. The respective VO2 (ml · kg · min–1) and HR (beats/min) values for each condition were FM 25.19 ± 3.6, 142 ± 11; BM 24.24 ± 2.7, 145 ± 12; and LM 30.5 ± 4.6, 160 ± 13. No differences were observed for RER or RPE.

Conclusions:

At self-selected intensities all 3 modes met criteria for maintaining cardiovascular fitness. Practitioners can use these results to develop rehabilitation programs based on clients’ perception and level of discomfort

Restricted access

Renee Newcomer Appaneal, Frank M. Perna and Kevin T. Larkin

Features of posttraumatic distress have been associated with treatment noncompliance and delayed surgical recovery among general medical and trauma populations. Although cognitive-affective and behavioral features of posttraumatic distress have been demonstrated among adult and adolescent athletes with injuries, physiological responses associated with posttraumatic distress have not yet been examined in this population. The objective of this study was to examine psychophysiological stress reactivity to orthopedic trauma among male athletes who sustained a severe sport injury. Athletes with injuries (n= 7) and non-injured athlete controls (n= 5) completed self-report measures of psychological distress and were then shown injury video footage while heart rate and skin conductance measures were recorded. After exposure to orthopedic trauma-related video footage, athletes with injuries demonstrated significantly greater skin conductance reactivity and subjective distress compared to controls. As demonstrated among other medical and trauma populations, athletes with injuries exhibit exaggerated stress reactivity profiles when primed with orthopedic trauma stimuli.

Restricted access

Kamuran Yerlikaya Balyan, Serdar Tok, Arkun Tatar, Erdal Binboga and Melih Balyan

The present study examined the association between personality, competitive anxiety, somatic anxiety and physiological arousal in athletes with high and low anxiety levels. Anxiety was manipulated by means of an incentive. Fifty male participants, first, completed the Five Factor Personality Inventory and their resting electro dermal activity (EDA) was recorded. In the second stage, participants were randomly assigned to high or low anxiety groups. Individual EDAs were recorded again to determine precompetition physiological arousal. Participants also completed the Competitive State Anxiety Inventory-2 (CSAI-2) and played a computer-simulated soccer match. Results showed that neuroticism was related to both CSAI-2 components and physiological arousal only in the group receiving the incentive. Winners had higher levels of cognitive anxiety and lower levels of physiological arousal than losers. On the basis of these findings, we concluded that an athlete’s neurotic personality may influence his cognitive and physiological responses in a competition.

Restricted access

Peter J. Lang

Emotions are organized around 2 basic motivational systems, appetitive and defensive, that evolved from primitive neural circuits in the mammalian brain. The appetitive system is keyed for approach behavior, founded on the preservative, sexual, and nurturant reflexes that underlie pleasant affects; the defense system is keyed for withdrawal, founded on protective and escape reflexes that underlie unpleasant affects. Both systems control attentional processing: Distal engagement by motive-relevant cues prompts immobility and orienting. With greater cue proximity (e.g., predator or prey imminence), neural motor centers supercede, determining overt defensive or consummatory action. In humans, these systems determine affective expression, evaluation behavior, and physiological responses that can be related to specific functional changes in the brain. This theoretical approach is illustrated with psychophysiological and brain imagery studies in which human subjects respond to emotional picture stimuli.

Restricted access

Sarah E. Williams, Jennifer Cumming and George M. Balanos

The present study investigated whether imagery could manipulate athletes’ appraisal of stress-evoking situations (i.e., challenge or threat) and whether psychological and cardiovascular responses and interpretations varied according to cognitive appraisal of three imagery scripts: challenge, neutral, and threat. Twenty athletes (M age = 20.85; SD = 1.76; 10 female, 10 male) imaged each script while heart rate, stroke volume, and cardiac output were obtained using Doppler echocardiography. State anxiety and self-confidence were assessed following each script using the Immediate Anxiety Measures Scale. During the imagery, a significant increase in heart rate, stroke volume, and cardiac output occurred for the challenge and threat scripts (p < .05). Although there were no differences in physiological response intensities for both stress-evoking scripts, these responses, along with anxiety symptoms, were interpreted as facilitative during the challenge script and debilitative during the threat script. Results support using imagery to facilitate adaptive stress appraisal.

Restricted access

Michael Wilkinson, Damon Leedale-Brown and Edward M. Winter

Purpose:

We examined the reproducibility of performance and physiological responses on a squash-specific incremental test.

Methods:

Eight trained squash players habituated to procedures with two prior visits performed an incremental squash test to volitional exhaustion on two occasions 7 days apart. Breath-by-breath oxygen uptake ( Vo2) and heart rate were determined continuously using a portable telemetric system. Blood lactate concentration at the end of 4-min stages was assessed to determine lactate threshold. Once threshold was determined, test speed was increased every minute until volitional exhaustion for assessment of maximal oxygen uptake (Vo2max), maximum heart rate (HRmax), and performance time. Economy was taken as the 60-s mean of Vo2 in the final minute of the fourth stage (below lactate threshold for all participants). Typical error of measurement (TEM) with associated 90% confidence intervals, limits of agreement, paired sample t tests, and least products regression were used to assess the reproducibility of scores.

Results:

Performance time (TEM 27 s, 4%, 90% CI 19 to 49 s) Vo2max (TEM 2.4 mL·kg−1·min−1, 4.7%, 90% CI 1.7 to 4.3 mL·kg−1·min−1), maximum heart rate (TEM 2 beats·min−1, 1.3%, 90% CI 2 to 4 beats·min−1), and economy (TEM 1.6 mL·kg−1·min−1, 4.1%, 90% CI 1.1 to 2.8 mL·kg−1·min−1) were reproducible.

Conclusions:

The results suggest that endurance performance and physiological responses to a squash-specific fitness test are reproducible.

Restricted access

William McGarvey, Richard Jones and Stewart Petersen

The purpose of this investigation was to examine the effect of interval (INT) and continuous (CON) cycle exercise on excess post-exercise oxygen consumption (EPOC). Twelve males first completed a graded exercise test for VO2max and then the two exercise challenges in random order on separate days approximately 1 wk apart. The INT challenge consisted of seven 2 min work intervals at 90% VO2max, each followed by 3 min of relief at 30% VO2max. The CON exercise consisted of 30 to 32 min of continuous cycling at 65% VO2max. Gas exchange and heart rate (HR) were measured for 30 min before, during, and for 2 h post-exercise. Three methods were used to analyze post-exercise oxygen consumption and all produced similar results. There were no significant differences in either the magnitude or duration of EPOC between the CON and INT protocols. HR, however, was higher (P < 0.05) while respiratory exchange ratio (RER) was lower (P < 0.05) following INT. These results indicate that when total work was similar, the magnitude and duration of EPOC were similar following CON or INT exercise. The differences in HR and RER during recovery suggest differential physiological responses to the exercise challenges.

Restricted access

Mindy L. Millard-Stafford, Phillip B. Sparling, Linda B. Rosskopf and Teresa K. Snow

Our purpose was to determine if sports drinks with 6 and 8% CHO differentially affect physiological responses or run performance in the heat. Ten men ran 32 km while ingesting: placebo (P), 6% carbohydrate-electrolyte (CE6), and 8% carbohydrate-electrolyte (CE8). At 15 km, a 250 mL drink labeled with deuterium oxide (D2O) was ingested. Blood glucose and respiratory exchange ratio were significantly higher (P < 0.05) for CE6 and CE8 compared to P. Rectal temperature (Tre) at 32 km was higher for CE8 (40.1 ± 0.2 °C) compared to P (39.5 ± 0.2 °C) but similar to CE6 (39.8 ± 0.2 °C). D2O accumulation was not different among drink trials. Run performance was 8% faster for CE8 (1062 ± 31 s) compared to P (1154 ± 56 s) and similar to CE6 (1078 ± 33 s). Confirming the ACSM Position Stand, 8% CE are acceptable during exercise in the heat and attenuate the decline in performance.