Running-induced fatigue and impact loading in runners: A systematic review and meta-analysis.

This systematic review and meta-analysis aimed to synthesise and clarify the effect of running-induced fatigue on impact loading during running. Eight electronic databases were systematically searched until April 2021. Studies that analysed impact loading over the course of a run, in adult runners free of medical conditions were included. Changes in leg stiffness, vertical stiffness, shock attenuation, peak tibial accelerations, peak ground reaction forces (GRF) and loading rates were extracted. Subgroup analyses were conducted depending on whether participants were required to run to exhaustion. Thirty-six studies were included in the review, 25 were included in the meta-analysis. Leg stiffness decreased with running-induced fatigue (SMD -0.31, 95% CI -0.52, -0.08, moderate evidence). Exhaustive and non-exhaustive subgroups were different for peak tibial acceleration (Chi2 = 3.79, p = 0.05), with limited evidence from exhaustive subgroups showing an increase in peak tibial acceleration with fatigue. Findings for vertical GRF impact peak and peak braking force were conflicting based on exhaustive and non-exhaustive protocols (Chi2 = 3.83, p = 0.05 and Chi2 = 5.10, p = 0.02, respectively). Moderate evidence suggests leg stiffness during running decreases with fatigue. Given the non-linear relationship between leg stiffness and running economy, this may have implications for performance.

Core self-evaluation as a predictor of strength training adoption in older adults.

OBJECTIVE: Progressive resistance training (PRT) counteracts sarcopenia and has been demonstrated to improve physical function and quality of life in older adults. Despite the clear benefits of PRT, participation remains low. The core self-evaluation (CSE) construct is theoretically antecedent to four personality traits: locus of control, self-esteem, neuroticism (emotional stability), and generalized self-efficacy. We have examined the association of CSE with exercise adoption among older adults invited to participate in a PRT trial. We hypothesized that CSE would positively predict adoption of PRT. STUDY DESIGN: All residents of two retirement communities were invited to complete questionnaires with items on demographics, physical activity, CSE, and general health. Following completion of questionnaires, residents were invited to take part in an on-site, 10-week randomized controlled trial of a PRT-based exercise trial. RESULTS: Thirty-eight of 358 residents (63.2% women; 76.6±6.1 year; range 58-92) enrolled and 118 residents completed the questionnaires. Multiple regression analysis predicting PRT adoption indicated that the demographic variables accounted for 38% of the variance. Inclusion of CSE (ß=.405) accounted for an additional 10% of the variance in PRT adoption. CONCLUSION: CSE was predictive of PRT adoption in this cohort, adding significantly to the predictive efficacy of known demographic predictors. This is the first study to show that CSE may influence adoption of PRT in any cohort.

Efficacy and feasibility of a novel tri-modal robust exercise prescription in a retirement community: a randomized, controlled trial.

OBJECTIVES: To test the feasibility and efficacy of current guidelines for multimodal exercise programs in older adults. DESIGN: Randomized, controlled trial. SETTING: Retirement village. PARTICIPANTS: Thirty-eight subjects (14 men and 24 women) aged 76.6 +/- 6.1. INTERVENTION: A wait list control or 10 weeks of supervised exercise consisting of high-intensity (80% of one-repetition maximum (1RM)) progressive resistance training (PRT) 3 days per week, moderate-intensity (rating of perceived exertion 11 to 14/20) aerobic training 2 days per week, and progressive balance training 1 day per week. MEASUREMENTS: Blinded assessments of dynamic muscle strength (1RM), balance, 6-minute walk, gait velocity, chair stand, stair climb, depressive symptoms, self-efficacy, and habitual physical activity level. RESULTS: Higher baseline strength and psychological well-being were associated with better functional performance. Strength gains over 10 weeks averaged 39+/-31% in exercise, versus 21+/-24% in controls (P=.10), with greater improvements in hip flexion (P=.01), hip abduction (P=.02), and chest press (P=.04) in the exercise group. Strength adaptations were greatest in exercises in which the intended continuous progressive overload was achieved. Stair climb power (12.3+/-15%, P=.002) and chair stand time (-7.1+/-15%, P=.006) improved significantly and similarly in both groups. Reduction in depressive symptoms was significantly related to compliance (attendance rate r=-0.568, P=.009, PRT progression in loading r=-0.587, P=.02, and total volume of aerobic training r=-0.541, P=.01), as well as improvements in muscle strength (r=-0.498, P=.002). CONCLUSION: Robust physical and psychological adaptations to exercise are linked, although volumes and intensities of multiple exercise modalities sufficient to cause significant adaptation appear difficult to prescribe and adhere to simultaneously in older adults.