Chronological changes in neuromuscular cooperativeness before and after muscle fatigue loading using the silent period of the quadriceps and hamstrings in young female athletes.
Sakiko Ito-Oonishi, Masahiro Takemura, Akihiro Kanamori and 2 others
PMID 34873372WHAT IT FOUND
Fatigue loading prolonged a lab measure of quadriceps-hamstring switching in the fatigued leg immediately and for 5 minutes.
Pre-motor time did not change.
Key findings
01The switching silent period was significantly prolonged on the loaded leg immediately and 5 minutes after fatigue loading; mean values were 42.7 ms before loading, 87.7 ms immediately after, and 75.1 ms at 5 minutes.
02Pre-motor time showed no main effect for any factor after fatigue loading.
03No significant SSP differences were observed before and after loading on the non-loaded leg.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
The study included only 15 healthy female university athletes, so the results cannot be generalised to male athletes, older adults, recreational athletes, or people with injuries. The outcome was a laboratory EMG timing measure, not a clinical function, sport performance measure, or injury outcome. Subjective fatigue and the specific central mechanism were not measured, so the study cannot say how much fatigue the athletes felt or why the timing changed. The authors did not examine different fatigue loading doses or recovery after ACL reconstruction or other lower limb injuries. The non-fatigued leg served as an internal comparison, but the paper did not report randomisation, blinding, or a separate control group.
Declared interests
The authors declared no conflict of interest.
The easy way to misread this
Do not conclude that fatigue loading increases injury risk or that this test can guide return-to-play decisions. The study measured a laboratory EMG timing variable in 15 healthy female athletes and did not assess injuries, sport performance, or patients with lower limb conditions.