The Influence Of Foot Stance On Force-Time Curve Parameters During Hand Grip Performance

Abstract

PURPOSE: To assess the differences in foot position on bilateral grip strength. METHODS: Nineteen recreationally active men (22.74±3.25yr; 77.86±12.90kg; 173.69±6.58cm) performed nine randomly assigned experimental trials consisting of maximal handgrip (HG) performance in both dominant (H1) and non-dominant (H2) hands measured simultaneously with a HG dynamometer. Bilateral HG was measured in three different stances [neutral (N), dominant foot forward (D), and non-dominant foot forward (ND)] consisting of three trials each. Subjects grasped as hard as possible for 6s during each trial with a recovery period of 60s between trials. A Waterloo Footedness Questionnaire was used to determine subject foot dominance, while the hand with the highest PF measured in N stance, was considered the H1 hand. The HG dynamometer was connected to a data acquisition system and the force-time curve was analyzed using computer software. The variables measured were: peak force (PF), rate of force development (RFD), time to PF (TPF), force at peak RFD ([email protected]), impulse [area under the curve for the first second (AUC1) and the first two seconds (AUC2)], and time to 90% of PF (T90PF). Repeated measures analysis of variance (RM ANOVA) was used to determine differences in all variables between hands during the three stances. RESULTS: The H1 hand was greater than the H2 hand in PF (42.16±1.50kg vs. 39.12±1.48kg, p<0.001) and [email protected] (35.31±1.46kg vs. 33.31±1.33kg, p<0.001) independent of stance. Significant hand×stance interactions were found for TPF (p = 0.010, η2 = 0.228) and AUC1 (p = 0.008, η2 = 0.233). Follow-up analyses showed TPF during the ND stance was shorter in H1 compared to H2 (1.17s vs. 1.53s, p=0.031), while H2 had greater AUC1 in the D stance as compared to the N stance (1.16N·s vs. 1.10N·s, p=0.043). No differences were observed for RFD, AUC2, and T90PF. CONCLUSIONS: While maximal HG force or RFD does not appear to be influenced by foot stance, the time needed and ability to generate HG force may be influenced by the ipsilateral/contralateral configuration of the dominant and non-dominant limbs.