Runners With Midportion Achilles Tendinopathy Have Joint-Specific Work Deficits When Compared To Matched Controls

Purpose: To determine the differences in drop countermovement jump (DCMJ) performance and lower extremity mechanics in runners with midportion AT and matched control (CON) participants. Methods: Runners with unilateral midportion AT (n = 21, 10 females) were compared to age and sex (assigned at birth) matched control runners (n = 21, 10 females). All participants performed 3-6 trials of a single leg DCMJ which involved jumping off a 20 cm box. Pain during and after jump performance was assessed using a numeric pain rating scale. Three-dimensional lower extremity kinematic and kinetic data was collected using an eight-camera system (Qualisys, Sweden) at 120 Hz and two embedded force plates (Kistler, Switzerland) sampled at 1200 Hz. The DCMJ was divided into two phases: braking and propulsion. Between-group differences were analyzed using one-sided paired t test (p < 0.05). The effects of group (AT, CON) and sex were explored using a linear mixed effects (LME) model for each dependent variable (net hip, knee, ankle and total limb work during the braking and propulsion phases) in JMP (SAS Institute Inc., USA) with α = 0.05. Results: No pain was reported during or after DCMJ trials. The mean jump height for runners with AT was lower than matched controls (p = 0.01) (Table 1). The LME model revealed that there was no significant group x sex interaction for any dependent variable. During the braking phase, runners with AT exhibited significantly lower net knee work (p = 0.03) and net total limb work (p = 0.01) (Table 1). In the propulsion phase, runners with AT demonstrated reduced net knee work (p = 0.04), net ankle work (p = 0.01), and net total limb work (p = 0.01) compared to controls (Table 1). Additionally, female participants showed lower net ankle (p = 0.01) and net total limb work (p = 0.04) during the propulsion phase when compared to males. Conclusion: Runners with AT exhibit reduced joint work during DCMJ, highlighting the impact of AT on energy absorption and return during high-demand tasks. Supported by: SR was supported by NIDDK R01DK114428, NIAMS R01AR079182, NIH NCATS UL1TR001445, Georgeny High Priority Award and Foundation for Physical Therapy Research