Added mass increases Achilles tendon stress in female runners

• Published in: Foot (Edinburgh, Scotland) Vol. 56; p. 102028
• Main Authors: De Starkey, Katelyn R., Groth, Ashley M., Thyssen, Ryan R., Kernozek, Thomas W.
• Format: Journal Article
• Language: English
• Published: Scotland Elsevier Ltd 01.09.2023
• Subjects: Biomechanics; Kinetics; Motion analysis; Musculoskeletal modeling; Training; Biomechanics; Training; Musculoskeletal modeling; Kinetics; Motion analysis
• ISSN: 0958-2592; 1532-2963
• DOI: 10.1016/j.foot.2023.102028

Achilles tendon (AT) injuries are common in female runners and military personnel where increased AT loading may be a contributing factor. Few studies have examined AT stress during running with added mass. The purpose was to examine the stress, strain, and force placed on the AT, kinematics and temporospatial variable in running with different amounts of added mass. Repeated measure design Twenty-three female runners with a rear-foot strike pattern were participants. AT stress, strain, and force were measured during running using a musculoskeletal model that used kinematic (180 Hz) and kinetic data (1800 Hz) as input. Ultrasound data were used to measure AT cross sectional area. A repeated measures multivariate analysis of variance (α = 0.05) was used on AT loading variables, kinematics and temporospatial variables. Peak AT stress, strain, and force were greatest during the 9.0 kg added load running condition (p < .0001). There was a 4.3% and 8.8% increase in AT stress and strain during the 4.5 kg and 9.0 kg added load conditions, respectively, compared to baseline. Kinematics at the hip and knee changed with added load but not at the ankle. Small changes in temporospatial variables were seen. Added load increased stress on the AT during running. There may be an increased risk for AT injury with added load. Individuals may consider slowly progressing training with added load to allow for increased AT loading. •This study compared the effects of added loads to female runners.•Achilles tendon stress and strain increased with added loads.•Changes in hip and knee kinematics were observed with added loads.•Cadence, stride length and stance time did not change with added loads.