Context: Lacking ankle flexibility or dorsiflexion range of motion (DFROM) has been postulated to be a primary risk factor in lower extremity injuries. The soleus has not been well investigated for stretching to gain DFROM or for its relation to DFROM in sport. Objective: The purpose of this research is to investigate soleus and gastrocnemius length and their relationship to DFROM in a two-pronged approach: 1) the effect of soleus specific stretching on increasing DFROM as compared to traditional gastrocnemius/soleus stretching; and 2) an exploration of whether a relationship exists between shortening of the gastrocnemius or soleus and the sport type an athlete engages in. Design: 1) Randomized controlled clinical trial; 2) Cross sectional study. Setting: 1) Collegiate athletes during in-season, 2) Collegiate pre-season physical examination records. Patients or Other Participants: 1) Final measures on 132 ankles, 61 male and 71 female, from six teams each separately randomly assigned to knee flexed (soleus) stretching, knee-extended (gastrocnemius/soleus) stretching and control groups; 2) Physical examination records reviewed on 339 athletes or 678 ankles after exclusions, 178 males and 161 females. Interventions: 1) The two stretching groups were asked to perform three 30-second stretches on each leg twice a day beyond the teams’ usual stretching protocol for four weeks. The control group continued to perform the team stretching protocol. Main Outcome Measures: Non-weight-bearing DFROM with the knee extended (KE) and with the knee flexed to 90 degrees (KF). Results: 1) Soleus stretching caused a statistically significant gain on the KE measurement as compared to the control group. The traditional gastrocnemius/soleus-stretching group had a gain but this did not reach significance. There was no statistically significant difference in the two stretching groups. 2) Basketball had statistically significant less DFROM on both KE and KF as compared to Endurance and Non-endurance sport types respectively. No statistically significant difference between the Endurance and Non-endurance groups. Conclusions: 1) Soleus specific (knee-flexed) stretching for four weeks during the competitive season for collegiate athletes caused a statistically significant gain in DFROM compared to a control group and greater gains as compared to traditional knee-extending stretching. 2) Basketball had significant DFROM flexibility restrictions both KE and KF compared to the other sports on a robust set of measures. The mean DFROM for all teams is very restricted compared to norms, classifications, and cut-off point for risk studies.
