Side-to-side asymmetry in lower limb strength and hamstring-quadriceps strength ratio among collegiate American football players.
Enver Tatlıcıoğlu, Ozan Atalağ, Berkiye Kırmızıgil and 2 others
PMID 31871371WHAT IT FOUND
Hamstring-to-quadriceps strength ratios looked normal in collegiate American football players, but side-to-side asymmetry appeared at the faster strength test.
Key findings
01At 60°/s, dominant-leg quadriceps peak torque was higher than non-dominant-leg quadriceps peak torque, while hamstring peak torque did not differ.
02Hamstring-to-quadriceps ratios were reported as normal at both 60°/s and 300°/s using the >60 cut-off.
03At 300°/s, limb asymmetry index values were negative for quadriceps and hamstring, indicating side-to-side asymmetry when the 10% cut-off was used.
STILL TO COME
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What it does not show
Only 26 collegiate American football players were tested, so the strength values may not represent other athletes. All participants were right-leg dominant, so results may not apply to athletes with other leg dominance. The study measured concentric isokinetic peak torque only; eccentric testing and functional hamstring-to-quadriceps ratios were not assessed. Interpretation depended on cut-off values, and the authors note there is no consensus for limb asymmetry index and hamstring-to-quadriceps cut-offs. The paper reports strength test results, not injury outcomes, so it does not show that these asymmetries predicted injuries.
Declared interests
None declared.
The easy way to misread this
Do not read these strength asymmetries as proof of injury risk. The study measured strength in collegiate American football players and did not report injuries.