Effects Of Arm Swing On Peak Power Production During Countermovement Jumping In Male And Female Weightlifters

BACKGROUND: Performing the countermovement jump (CMJ) with arm swing (AS) has been shown to increase CMJ performance compared to performance without AS (NAS); however, investigations using healthy non-athletes or jumping sport athletes report that males benefit more from AS than females. Olympic weightlifters (OWL) are power sport athletes, and while their events involve triple extension, they are not jumping sport athletes thereby possibly providing unique insight into AS CMJ augmentation sex differences. The study sought to assess sex differences of AS on peak power (PP), force at peak power (FPP) and velocity at peak power (VPP) during CMJ performed by OWL. METHODS: Female (n = 25) and male (n = 28) OWL national meet qualifiers (18-35 yrs) completed three maximal effort CMJ with and without (akimbo) AS in a randomized order with one minute rest between trials. During each CMJ, vertical ground reaction forces were collected and used to compute PP (W/kg), FPP (N/kg), and VPP (m/s). For each outcome measure, post hoc testing of significant (P < .05) sex by AS analysis of variance effects were interpreted using 95% confidence interval differences (95% CIdiff). RESULTS: Males exhibited significantly greater PP than females for NAS (95% CIdiff = 3.5-12.0, d = .97) and AS (95% CIdiff = 11.1-28.0, d = 1.2). PP with AS was significantly greater than NAS for males (95% CIdiff = 11.6-22.1, d = 1.2) but not females (95% CIdiff = -0.5-10.6, d = .49). Males exhibited significantly greater VPP than females for NAS (95% CIdiff = 0.15-0.40, d = 1.2) and AS (95% CIdiff = 0.42-0.91, d = 1.4). VPP with AS was significantly greater than NAS for males (95% CIdiff = 0.30-0.64, d = 1.2) but not females (95% CIdiff = -0.26-0.09, d = .24). For FPP, while FPP with AS was significantly greater than NAS (95% CIdiff = 0.9-0.20, d = .66), there was no significance between the males and females (95% CIdiff = -0.001-0.21, d = .47). CONCLUSIONS: These results show male OWL also demonstrate greater AS CMJ performance benefits than females, thereby extending previous work in healthy adults and jumping athletes. Unique was the identification that VPP explains the greater PP by the males. The tendency of males to have greater upper extremity mass, which in turn imparts greater influence on their center of mass may explain the VPP benefit but will need to be confirmed with future research.