The Immediate Effects of Expert and Dyad External Focus Feedback on Drop Landing Biomechanics in Female Athletes: An Instrumented Field Study.
Kelly A Leonard, Janet E Simon, Jae Yom and 1 others
PMID 33604139WHAT IT FOUND
Expert feedback lowered landing impact force; teammate feedback did not.
Both groups reduced the knee moving inward after one session. For impact force, only expert feedback changed; for inward knee movement, teammate feedback was similar.
Key findings
01After feedback, the expert group decreased vertical ground reaction force by 0.72 N*bw-1, while the dyad group did not significantly change (0.18 N*bw-1).
02Knee abduction displacement decreased by 4.65° after feedback in both groups, with no significant difference between groups.
03In individual change analysis, more expert athletes exceeded minimal detectable change for knee flexion displacement (84.6% vs 30%) and vGRF (84.6% vs 20%) than dyad athletes.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
Only 23 female basketball and volleyball athletes from one college were studied, so results may not apply to other athletes or settings. Teams were randomized as whole teams, so feedback group is mixed with sport and team, making it hard to separate the effect of expert versus dyad feedback. The study measured only immediate effects after one feedback session, not whether changes lasted or reduced ACL injury rates. The feedback task was squat jump landing, while the tested task was drop vertical jump, so transfer may be limited. Sample size was small and may have been underpowered for knee flexion displacement. Only the first landing of the drop vertical jump was analysed.
Declared interests
The authors reported no conflicts of interest.
The easy way to misread this
Do not conclude that teammate feedback can replace expert feedback for reducing landing impact force. The dyad group did not significantly change vGRF (0.18 N*bw-1), while the expert group decreased it by 0.72 N*bw-1.