Hypothetical question for any PT
Suppose you were a physical therapist who was interested in determining if a new ACL rehabilitation technique helped soccer players regain their pre-injury performance levels more quickly than existing ACL rehabilitation techniques. For your research, you utilize a pre/post test of 1RM knee extension (using an isokinetic device) and, for your intervention, soccer players with the same ACL injuries are rehabilitated with either the new technique or an older, existing technique. Your results show that players who rehabbed with the new technique had a significantly higher 1RM than the old technique group after 6 weeks of rehabilitation.
In addition, the 1RM of the new rehab group appeared to be almost the same as pre-injury levels.
However, when these same players attend their first soccer practice, it is clear that both the old and new groups perform equally well (with respect to their soccer skills).
In other words, your research suggested one technique was superior but this did not hold true in the actual soccer setting.
What could you have done differently to ensure your results were a more accurate reflection of soccer performance?
1 Comment found
BillW
First of all, I would never use 1RM of knee extensions after an ACL injury, as this exercise would be contraindicated as it pusts stress on the new ACL. Secondly open chain exercises (ex done with foot not on a surface) have not been show to coorelate well to function, again suggesting that knee extensions would be a poor choice for testing. I would have used a closed chain activity (foot planted, example squat/lunge) that incorporated some level of balance and proprioception. You would have to be very careful in the first 6 wks though with what you do to avoid injurying the new ACL. I would perform these tests on the injured, and non-injured leg, and see which group had the injured leg return to the level of the non-injured leg first (or at least 80% of the non-injured leg). This would give you a better idea which technique returned the injured leg to a soccer ready position first. Remember if you test them both at 20 wks, they may both be at the same place, whereas, had they been tested at 16 wks, one may be in front of the other, allowing a quicker return to sport.