Do alterations in muscle strength, flexibility, range of motion, and alignment predict lower extremity injury in runners: a systematic review.
Shefali M Christopher, Jeremy McCullough, Suzanne J Snodgrass and 1 others
PMID 30805204WHAT IT FOUND
No muscle strength, flexibility, range-of-motion, or alignment test reliably predicted running injury across seven studies.
Some isolated associations appeared, but they were inconsistent and not strong enough to guide practice.
Key findings
01Across seven included studies, the review found no compelling evidence that any lower-extremity clinical test consistently predicted running injury.
02All clinical assessment categories had very low quality evidence, and the authors advised caution when interpreting isolated findings.
03Some individual studies reported significant associations, such as stronger hip abduction associated with injury and a higher hip external-to-internal rotation strength ratio associated with lower injury, but these were not replicated across studies.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
Only seven studies were included, and each assessment category was based on at most three studies. All included studies were observational, and the review rated every clinical assessment category as very low quality. The studies used different ways to measure the same tests, different injury definitions, different runner populations, and different statistical models, so results could not be combined. Many studies did not report key risk factors such as weekly mileage or previous injury, and some did not report reliability or validity of the measures. Post-operative runners and military runners were excluded, so the findings may not apply to those groups. Some significant findings came from a single study and were not replicated, such as hip abduction strength and navicular drop.
The easy way to misread this
Do not conclude that stronger hip abduction or a higher hip external-to-internal rotation ratio predicts or prevents running injury. These findings came from single studies, were not replicated, and the overall evidence was very low quality.