Search Results

You are looking at 71 - 80 of 933 items for :

Clear All
Restricted access

David M. Williams

The article reviews research relevant to a proposed conceptual model of exercise adherence that integrates the dual mode model and hedonic theory. Exercise intensity is posited to influence affective response to exercise via interoceptive (e.g., ventila-tory drive) and cognitive (e.g., perceived autonomy) pathways; affective response to exercise is posited to influence exercise adherence via anticipated affective response to future exercise. The potential for self-paced exercise to enhance exercise adherence is examined in the context of the proposed model and suggestions are given for future research. Further evidence in support of self-paced exercise could have implications for exercise prescription, especially among overweight, sedentary adults, who are most in need of interventions that enhance adherence to exercise programs.

Restricted access

Inge K. Stoter, Brian R. MacIntosh, Jared R. Fletcher, Spencer Pootz, Inge Zijdewind and Florentina J. Hettinga

Purpose:

To evaluate pacing behavior and peripheral and central contributions to muscle fatigue in 1500-m speed-skating and cycling time trials when a faster or slower start is instructed.

Methods:

Nine speed skaters and 9 cyclists, all competing at regional or national level, performed two 1500-m time trials in their sport. Athletes were instructed to start faster than usual in 1 trial and slower in the other. Mean velocity was measured per 100 m. Blood lactate concentrations were measured. Maximal voluntary contraction (MVC), voluntary activation (VA), and potentiated twitch (PT) of the quadriceps muscles were measured to estimate central and peripheral contributions to muscle fatigue. In speed skating, knee, hip, and trunk angles were measured to evaluate technique.

Results:

Cyclists showed a more explosive start than speed skaters in the fast-start time trial (cyclists performed first 300 m in 24.70 ± 1.73 s, speed skaters in 26.18 ± 0.79 s). Both trials resulted in reduced MVC (12.0% ± 14.5%), VA (2.4% ± 5.0%), and PT (25.4% ± 15.2%). Blood lactate concentrations after the time trial and the decrease in PT were greater in the fast-start than in the slow-start trial. Speed skaters showed higher trunk angles in the fast-start than in the slow-start trial, while knee angles remained similar.

Conclusions:

Despite similar instructions, behavioral adaptations in pacing differed between the 2 sports, resulting in equal central and peripheral contributions to muscle fatigue in both sports. This provides evidence for the importance of neurophysiological aspects in the regulation of pacing. It also stresses the notion that optimal pacing needs to be studied sport specifically, and coaches should be aware of this.

Restricted access

Rich D. Johnston, Tim J. Gabbett and David G. Jenkins

Purpose:

To assess the influence of playing standard and physical fitness on pacing strategies during a junior team-sport tournament.

Methods:

A between-groups, repeated-measures design was used. Twenty-eight junior team-sport players (age 16.6 ± 0.5 y, body mass 79.9 ± 12.0 kg) from a high-standard and low-standard team participated in a junior rugby league tournament, competing in 5 games over 4 d (4 × 40-min and 1 × 50-min game). Players wore global positioning system (GPS) microtechnology during each game to provide information on match activity profiles. The Yo-Yo Intermittent Recovery Test (level 1) was used to assess physical fitness before the competition.

Results:

High-standard players had an initially higher pacing strategy than the low-standard players, covering greater distances at high (ES = 1.32) and moderate speed (ES = 1.41) in game 1 and moderate speed (ES = 1.55) in game 2. However, low-standard players increased their playing intensity across the competition (ES = 0.57–2.04). High-standard/high-fitness players maintained a similar playing intensity, whereas high-standard/low-fitness players reduced their playing intensities across the competition.

Conclusions:

Well-developed physical fitness allows for a higher-intensity pacing strategy that can be maintained throughout a tournament. High-standard/low-fitness players reduce playing intensity, most likely due to increased levels of fatigue as the competition progresses. Low-standard players adopt a pacing strategy that allows them to conserve energy to produce an “end spurt” in the latter games. Maximizing endurance fitness across an entire playing group will maximize playing intensity and minimize performance reductions during the latter stages of a tournament.

Restricted access

Thomas I. Gee, Duncan N. French, Karl C. Gibbon and Kevin G. Thompson

Purpose:

This study investigated the pacing strategy adopted and the consistency of performance and related physiological parameters across three 2000-m rowing-ergometer tests.

Methods:

Fourteen male well-trained rowers took part in the study. Each participant performed three 2000-m rowing-ergometer tests interspersed by 3–7 d. Throughout the trials, respiratory exchange and heart rate were recorded and power output and stroke rate were analyzed over each 500 m of the test. At the completion of the trial, assessments of blood lactate and rating of perceived exertion were measured.

Results:

Ergometer performance was unchanged across the 3 trials; however, pacing strategy changed from trial 1, which featured a higher starting power output and more progressive decrease in power, to trials 2 and 3, which were characterized by a more conservative start and an end spurt with increased power output during the final 500 m. Mean typical error (TE; %) across the three 2000-m trials was 2.4%, and variability was low to moderate for all assessed physiological variables (TE range = 1.4−5.1%) with the exception of peak lactate (TE = 11.5%).

Conclusions:

Performance and physiological responses during 2000-m rowing ergometry were found to be consistent over 3 trials. The variations observed in pacing strategy between trial 1 and trials 2 and 3 suggest that a habituation trial is required before an intervention study and that participants move from a positive to a reverse-J-shaped strategy, which may partly explain conflicting reports in the pacing strategy exhibited during 2000-m rowing-ergometer trials.

Restricted access

Kevin De Pauw, Bart Roelands, Jef Vanparijs and Romain Meeusen

Purpose:

To determine the effect of active recovery (AR), passive rest (PR), and cold-water immersion (CWI) after 90 min of intensive cycling on a subsequent 12-min time trial (TT2) and the applied pacing strategy in TT2.

Methods:

After a maximal test and familiarization trial, 9 trained male subjects (age 22 ± 3 y, VO2max 62.1 ± 5.3 mL · min−1 · kg−1) performed 3 experimental trials in the heat (30°C). Each trial consisted of 2 exercise tasks separated by 1 h. The first was a 60-min constant-load trial at 55% of the maximal power output followed by a 30-min time trial (TT1). The second comprised a 12-min simulated time trial (TT2). After TT1, AR, PR, or CWI was applied for 15 min.

Results:

No significant TT2 performance differences were observed, but a 1-sample t test (within each condition) revealed different pacing strategies during TT2. CWI resulted in an even pacing strategy, while AR and PR resulted in a gradual decline of power output after the onset of TT2 (P ≤ .046). During recovery, AR and CWI showed a trend toward faster blood lactate ([BLa]) removal, but during TT2 significantly higher [BLa] was only observed after CWI compared with PR (P = .011).

Conclusion:

The pacing strategy during subsequent cycling performance in the heat is influenced by the application of different postexercise recovery interventions. Although power was not significantly altered between groups, CWI enabled a differently shaped power profile, likely due to decreased thermal strain.

Restricted access

Andrew Renfree, Julia West, Mark Corbett, Clare Rhoden and Alan St Clair Gibson

Purpose:

This study examined the determinants of pacing strategy and performance during self-paced maximal exercise.

Methods:

Eight well-trained cyclists completed two 20-km time trials. Power output, rating of perceived exertion (RPE), positive and negative affect, and iEMG activity of the active musculature were recorded every 0.5 km, confidence in achieving preexercise goals was assessed every 5 km, and blood lactate and pH were measured postexercise. Differences in all parameters were assessed between fastest (FAST) and slowest (SLOW) trials performed.

Results:

Mean power output was significantly higher during the initial 90% of FAST, but not the final 10%, and blood lactate concentration was significantly higher and pH significantly lower following FAST. Mean iEMG activity was significantly higher throughout SLOW. Rating of perceived exertion was similar throughout both trials, but participants had significantly more positive affect and less negative affect throughout FAST. Participants grew less confident in their ability to achieve their goals throughout SLOW.

Conclusions:

The results suggest that affect may be the primary psychological regulator of pacing strategy and that higher levels of positivity and lower levels of negativity may have been associated with a more aggressive strategy during FAST. Although the exact mechanisms through which affect acts to influence performance are unclear, it may determine the degree of physiological disruption that can be tolerated, or be reflective of peripheral physiological status in relation to the still to be completed exercise task.

Restricted access

Sabrina Skorski, Oliver Faude, Chris R. Abbiss, Seraina Caviezel, Nina Wengert and Tim Meyer

Purpose:

To date, there has been limited research examining the influence of pacing pattern (PP) on middle-distance swimming performance. As such, the purpose of the current study was to examine the influence of PP manipulation on 400-m freestyle swimming performance.

Methods:

15 front-crawl swimmers (5 female, 10 male; age 18 ± 2 y) performed 3 simulated 400-m swimming events. The initial trial was self-selected pacing (PPSS). The following 2 trials were performed in a counterbalanced order and required participants to complete the first 100 m more slowly (PPSLOW: 4.5% ± 2.2%) or quickly (PPFAST: 2.4% ± 1.6%) than the PPSS trial. 50-m split times were recorded during each trial.

Results:

Overall performance time was faster in PPSS (275.0 ± 15.9 s) than in PPFAST (278.5 ± 16.4 s, P = .05) but not significantly different from PPSLOW (277.5 ± 16.2 s, P = .22). However, analysis for practical relevance revealed that pacing manipulation resulted in a “likely” (>88.2%) decrease in performance compared with PPSS.

Conclusion:

Moderate manipulation of the starting speed during simulated 400-m freestyle races seems to affect overall performance. The observed results indicate that PPSS is optimal in most individuals, yet it seems to fail in some swimmers. Future research should focus on the identification of athletes possibly profiting from manipulations.

Restricted access

David M. Williams, Shira Dunsiger, Jessica A. Emerson, Chad J. Gwaltney, Peter M. Monti and Robert Miranda Jr.

Affective response to exercise may mediate the effects of self-paced exercise on exercise adherence. Fiftynine low-active (exercise <60 min/week), overweight (body mass index: 25.0–39.9) adults (ages 18–65) were randomly assigned to self-paced (but not to exceed 76% maximum heart rate) or prescribed moderate intensity exercise (64–76% maximum heart rate) in the context of otherwise identical 6-month print-based exercise promotion programs. Frequency and duration of exercise sessions and affective responses (good/bad) to exercise were assessed via ecological momentary assessment throughout the 6-month program. A regression-based mediation model was used to estimate (a) effects of experimental condition on affective response to exercise (path a = 0.20, SE = 0.28, f 2 = 0.02); (b) effects of affective response on duration/latency of the next exercise session (path b = 0.47, SE = 0.25, f 2 = 0.04); and (c) indirect effects of experimental condition on exercise outcomes via affective response (path ab = 0.11, SE = 0.06, f 2 = 0.10). Results provide modest preliminary support for a mediational pathway linking self-paced exercise, affective response, and exercise adherence.

Restricted access

Susan L. Murphy, Dylan M. Smith and Angela K. Lyden

Background:

In a previous pilot study, the effect of 2 types of activity pacing instruction, general versus tailored, on osteoarthritis symptoms was examined and fatigue improved in the tailored group. Because activity pacing involves instruction on physical activity engagement, we undertook this secondary analysis to examine how pacing instruction affected physical activity patterns.

Methods:

Thirty-two adults with knee or hip osteoarthritis, stratified by age and gender, received either tailored or general activity pacing instruction. All participants wore an accelerometer for 5 days that measured physical activity and allowed for repeated symptom assessment at baseline and 10-week follow-up. Activity patterns were assessed by examining physical activity variability (standard deviation of 5-day average activity counts per minute), and average activity level (5-day average activity counts per minute).

Results:

Physical activity variability decreased in the tailored group and increased in the general group. No significant group changes in average activity from baseline to 10-week follow-up were found.

Conclusion:

In this pilot study, type of activity pacing instruction affected objective physical activity patterns in adults with OA. Tailored activity pacing was more effective at reducing high and low activity bouts corresponding to the message of keeping a steady pace to reduce symptoms.

Restricted access

Giulia De Ioannon, Giuseppe Cibelli, Sergio Mignardi, Agnese Antonelli, Laura Capranica and Maria Francesca Piacentini

Purpose:

To evaluate the pacing strategy, rating of perceived exertion (RPE), and mood during a 78.1-km solo ultraendurance open-water swim.

Methods:

Before and after the event, anthropometric parameters, cortisol, and the profile of mood state (POMS) of 1 male athlete (age 48 y, height 172 cm, body mass 68 kg, body fat 7.2%, athletic achievement: Italian record holder of the Channel Swim) were ascertained. Every 3 h during the event, average swimming speed (SS), stroke rate, stroke length (SL), and RPE were recorded.

Results:

The athlete completed the event in 23:44 h:min. Compared with the first 3 h of swimming, decreases in SS (−33%) and SL (−25%) were observed between 18 h and 21 h. Thereafter, the athlete increased SS (+41%) and SL (+17%) between 21 h and the end. RPE steadily increased from the beginning to the last 6 h of swimming. Cortisol showed a 23-fold increase. After the event, POMS showed a 500% increase in fatigue, 44% decrease in tension, and 77% decrease in vigor.

Conclusion:

For the first time ever an athlete crossed the Adriatic Sea. This case study shows that the athlete adopted a variable pacing strategy to complete 78 km. Despite the athlete perceiving his effort at maximum during the last 6 h, the observed increases in SS at the end of the event might substantiate his high potential motivation to accomplish this challenging and unique event.