The effect of soft tissue manipulation and rest on knee extensor muscles fatigue: Do torque parameters and induced perception following muscle fatigue have enough reliability?

Effects of muscle fatigue on quadriceps muscle performance in healthy amateur soccer players

INTRODUCTION

Quadriceps femoris muscle (QFM) fatigue has a detrimental impact on athlete performance. Therefore, it is crucial to evaluate various performance parameters under fatigued conditions. This study aimed to assess the performance of the QFM during both concentric and eccentric contractions before and after fatigue in the lower extremities of healthy amateur soccer players.

METHOD

Twenty-four healthy amateur soccer players performed three consecutive knee extension and flexion movements concentrically and eccentrically at a velocity of 120°/s with maximum effort, using a Biodex dynamometer. Fatigue was induced by a protocol involving repetitive concentric knee extension and flexion movements at 120°/s, with a load of 50% of maximal voluntary isometric contraction (MVIC) of the QFM until its moment declined to 50% of MVIC. Separate 2-way analyses of variance were conducted to assess the influence of contraction and fatigue on various isokinetic parameters.

RESULTS

No significant interaction effect between contraction and fatigue was observed for any of the parameters. There was a significant main effect of fatigue on average power for both lower extremities. However, no significant main effect of fatigue was observed for normalized peak moment, angle of peak moment, moment at 0.2s, total work, acceleration, and deceleration times. In contrast, significant main effects of contraction were noted for normalized peak moment, moment at 0.2s, average power, acceleration, and deceleration times in both lower extremities.

CONCLUSION

Average power appeared as the most sensitive performance parameter to fatigue. To enhance QFM performance, emphasizing eccentric exercises during training and conditioning programs could be beneficial for athletes.

A systematic review of chiropractic care for fall prevention: rationale, state of the evidence, and recommendations for future research

BACKGROUND

Falls in older adults are a significant and growing public health concern. There are multiple risk factors associated with falls that may be addressed within the scope of chiropractic training and licensure. Few attempts have been made to summarize existing evidence on multimodal chiropractic care and fall risk mitigation. Therefore, the broad purpose of this review was to summarize this research to date. BODY: Systematic review was conducted following PRISMA guidelines. Databases searched included PubMed, Embase, Cochrane Library, PEDro, and Index of Chiropractic Literature. Eligible study designs included randomized controlled trials (RCT), prospective non-randomized controlled, observational, and cross-over studies in which multimodal chiropractic care was the primary intervention and changes in gait, balance and/or falls were outcomes. Risk of bias was also assessed using the 8-item Cochrane Collaboration Tool. The original search yielded 889 articles; 21 met final eligibility including 10 RCTs. One study directly measured the frequency of falls (underpowered secondary outcome) while most studies assessed short-term measurements of gait and balance. The overall methodological quality of identified studies and findings were mixed, limiting interpretation regarding the potential impact of chiropractic care on fall risk to qualitative synthesis.

CONCLUSION

Little high-quality research has been published to inform how multimodal chiropractic care can best address and positively influence fall prevention. We propose strategies for building an evidence base to inform the role of multimodal chiropractic care in fall prevention and outline recommendations for future research to fill current evidence gaps.