Psychological determinants of whole-body endurance performance

Background: No literature reviews have systematically identified and evaluated research on the psychological determinants of endurance performance, and sport psychology performance-enhancement guidelines for endurance sports are not founded on a systematic appraisal of endurance-specific research. Objective: A systematic literature review was conducted to identify practical psychological interventions that improve endurance performance and to identify additional psychological factors that affect endurance performance. Additional objectives were to evaluate the research practices of included studies, to suggest theoretical and applied implications, and to guide future research. Methods: Electronic databases, forward-citation searches, and manual searches of reference lists were used to locate relevant studies. Peer-reviewed studies were included when they chose an experimental or quasi-experimental research design, a psychological manipulation, endurance performance as the dependent variable, and athletes or physically-active, healthy adults as participants. Results: Consistent support was found for using imagery, self-talk, and goal setting to improve endurance performance, but it is unclear whether learning multiple psychological skills is more beneficial than learning one psychological skill. The results also demonstrated that mental fatigue undermines endurance performance, and verbal encouragement and head-to-head competition can have a beneficial effect. Interventions that influenced perception of effort consistently affected endurance performance. Conclusions: Psychological skills training could benefit an endurance athlete. Researchers are encouraged to compare different practical psychological interventions, to examine the effects of these interventions for athletes in competition, and to include a placebo control condition or an alternative control treatment. Researchers are also encouraged to explore additional psychological factors that could have a negative effect on endurance performance. Future research should include psychological mediating variables and moderating variables. Implications for theoretical explanations of endurance performance and evidence-based practice are described

Shoulder muscle endurance: the development of a standardized and reliable protocol

<p>Abstract</p> <p>Background</p> <p>Shoulder muscle fatigue has been proposed as a possible link to explain the association between repetitive arm use and the development of rotator cuff disorders. To our knowledge, no standardized clinical endurance protocol has been developed to evaluate the effects of muscle fatigue on shoulder function. Such a test could improve clinical examination of individuals with shoulder disorders. Therefore, the purpose of this study was to establish a reliable protocol for objective assessment of shoulder muscle endurance.</p> <p>Methods</p> <p>An endurance protocol was developed on a stationary dynamometer (Biodex System 3). The endurance protocol was performed in isotonic mode with the resistance set at 50% of each subject's peak torque as measured for shoulder external (ER) and internal rotation (IR). Each subject performed 60 continuous repetitions of IR/ER rotation. The endurance protocol was performed by 36 healthy individuals on two separate occasions at least two days apart. Maximal isometric shoulder strength tests were performed before and after the fatigue protocol to evaluate the effects of the endurance protocol and its reliability. Paired <it>t</it>-tests were used to evaluate the reduction in shoulder strength due to the protocol, while intraclass correlation coefficients (ICC) and minimal detectable change (MDC) were used to evaluate its reliability.</p> <p>Results</p> <p>Maximal isometric strength was significantly decreased after the endurance protocol (<it>P </it>< 0.001). The total work performed during the last third of the protocol was significantly less than the first third of the protocol (P < 0.05). The test-retest reliability of the post-fatigue strength measures was excellent (ICC >0.84).</p> <p>Conclusions</p> <p>Changes in muscular performance observed during and after the muscular endurance protocol suggests that the protocol did result in muscular fatigue. Furthermore, this study established that the resultant effects of fatigue of the proposed isotonic protocol were reproducible over time. The protocol was performed without difficulty by all volunteers and took less than 10 minutes to perform, suggesting that it might be feasible for clinical practice. This protocol could be used to induce local muscular fatigue in order to evaluate the effects of fatigue on shoulder kinematics or to evaluate changes in shoulder muscle endurance following rehabilitation.</p

The Effect of Mental Fatigue on Critical Power during cycling exercise

Purpose: Time-to-exhaustion (TTE) tests used in the determination of critical power (CP) and curvature constant (W) of the power-duration relationship are strongly influenced by the perception of effort (PE). This study aimed to investigate whether manipulation of the PE alters the CP and W. Methods: Eleven trained cyclists completed a series of TTE tests to establish CP and W under two conditions, following a mentally fatiguing (MF), or a control (CON) task. Both cognitive tasks lasted 30 min followed by a TTE test. Ratings of PE and heart rate (HR) were measured during each TTE. Blood lactate was taken pre and post each TTE test. Ratings of perceived mental and physical fatigue were taken pre- and post-cognitive task, and following each TTE test. Results: Perceived MF significantly increased as a result of the MF task compared to baseline and the CON task (P0.05). PE was significantly higher during TTE in the MF condition (P0.05). Neither cognitive task induced any change in CP (MF 253±51 vs. CON 247±58W; P>0.05), although W was significantly reduced in the MF condition (MF 2.3±4.5 vs. CON 2.9±6.3kJ; P<0.01). Conclusion: MF has no effect of CP, but reduces the W in trained cyclists. Lower lactate accumulation during TTE tests following MF, suggests that cyclists were not be able to fully expend W even though they exercised to volitional exhaustion

The Coupling of Peripheral Blood Pressure and Ventilatory Responses during Exercise in Young Adults with Cystic Fibrosis

Cystic fibrosis (CF) is commonly recognized as a pulmonary disease associated with reduced airway function. Another primary symptom of CF is low exercise capacity where ventilation and gas-exchange are exacerbated. However, an independent link between pathophysiology of the pulmonary system and abnormal ventilatory and gas-exchange responses during cardiopulmonary exercise testing (CPET) has not been established in CF. Complicating this understanding, accumulating evidence suggests CF demonstrate abnormal peripheral vascular function; although, the clinical implications are unclear. We hypothesized that compared to controls, relative to total work performed (WorkTOT), CF would demonstrate increased ventilation accompanied by augmented systolic blood pressure (SBP) during CPET.16 CF and 23 controls (age: 23±4 vs. 27±4 years, P = 0.11; FEV1%predicted: 73±14 vs. 96±5, P<0.01) participated in CPET. Breath-by-breath oxygen uptake ([Formula: see text]), ventilation ([Formula: see text]), and carbon dioxide output ([Formula: see text]) were measured continuously during incremental 3-min stage step-wise cycle ergometry CPET. SBP was measured via manual sphygmomanometry. Linear regression was used to calculate [Formula: see text] slope from rest to peak-exercise.Compared to controls, CF performed less WorkTOT during CPET (90±19 vs. 43±14 kJ, respectively, P<0.01). With WorkTOT as a covariate, peak [Formula: see text] (62±8 vs. 90±4 L/min, P = 0.76), [Formula: see text] (1.8±0.3 vs. 2.7±0.1 L/min, P = 0.40), and SBP (144±13 vs. 152±6 mmHg, P = 0.88) were similar between CF and controls, respectively; whereas CF demonstrated increased [Formula: see text] slope (38±4 vs. 28±2, P = 0.02) but lower peak [Formula: see text] versus controls (22±5 vs. 33±4 mL/kg/min, P<0.01). There were modest-to-moderate correlations between peak SBP with [Formula: see text] (r = 0.30), [Formula: see text] (r = 0.70), and [Formula: see text] (r = 0.62) in CF.These data suggest that relative to WorkTOT, young adults with mild-to-moderate severity CF demonstrate augmented [Formula: see text] slope accompanied by increased SBP during CPET. Although the underlying mechanisms remain unclear, the coupling of ventilatory inefficiency with increased blood pressure suggest important contributions from peripheral pathophysiology to low exercise capacity in CF