Kinematic And Kinetic Differences During A Conventional Deadlift With And Without Shoes

Abstract

Despite the popularity of deadlifting without shoes, little research has examined the kinematic and kinetic differences during a conventional deadlift when performing the exercise barefoot. Excess joint torque in the frontal plane can be indicative of injury. PURPOSE: To examine the differences in frontal plane mechanics of the lower extremity and force development during a conventional deadlift with and without shoes. METHODS: Thirty participants with a mean height and weight of 1.75±0.10 meters and 81.12±16.05 kg. Participants recruited had consistently performed the conventional deadlift for six or more months and strength training at least two days per week. During the participant’s first visit, a one repetition maximum (1RM) using NSCA guidelines was determined. A second visit occurred at least 72 hours or more after the 1RM testing. Kinematic and kinetic data were collected using a 15-camera Qualisys Oqus system (240Hz) and two Bertec force plates (1200Hz). Participants performed five consecutive reps at 70% of their 1RM in random order (shoes and barefoot). Visual 3D was used to process raw marker and force data and to calculate frontal plane joint moments at the hip, knee, and ankle during the concentric phase. A one-way MANOVA (p<0.05) was used to investigate the different footwear conditions. RESULTS: There was a statistically significant difference between shoes (-0.28 ± 0.11 Nm/kg) and no shoes (-0.38 ± 0.14 Nm/kg) for internal ankle eversion moments (p=0.018). No significant differences were detected for knee and hip abduction moments. Peak vertical ground reaction force in the barefoot condition (1035.2±281.4 N) was not significantly different than the shoe condition (1044.9±286.5 N). CONCLUSION: The absence of shoes created an increase in frontal plane ankle moments, but there was no change in the vertical force characteristics. An increased internal eversion moment did not affect the joint moments further up the kinetic chain despite undergoing similar loading patterns.