Acute upper body resistance exercise whereby the eccentric muscle action is overloaded (AEL) has demonstrated enhanced kinematic variables in the subsequent concentric phase compared to equivalent constant load (CL) practices (1,2). Repeated application of the AEL model is believed to promote superior chronic strength adaptations (1). Whether such enhancements of kinematic and physiological variables occur in the lower body with AEL protocols remains unclear (3,4). Therefore, the aim of this study was to investigate differences in concentric kinematic and neuromuscular variables in acute lower limb AEL and CL models. Multiple-joint resistance exercise was employed in the current study given the greater neuromuscular and coordination demands believed to lead to better transference of chronic strength gains to competition and mobility in athletic and clinical populations, respectively. Strength trained males (n=10) completed experimental test day sessions (AEL and CL) in a randomised, cross over study after baseline strength (3RM) and familiarisation sessions. Test day sessions required 4 sets of 3 back squat repetitions to be completed with either an AEL (105% of 3RM) and a lighter subsequent concentric phase (65%, 75%, 85% and 95% of 3RM) or CL where both phases were the same absolute load (65%, 75%, 85% and 95% of 3RM). Concentric phase kinematic variables and lower limb surface EMG were assessed. EMG was normalised to a submaximal back squat warm-up set as previously described (5). Repeated measures ANOVAs were conducted to assess differences between conditions (P<0.05). No statistically significant differences in concentric kinematic variables were detected (peak power [P=0.273, CL: 2700.7 ± 155.1W; AEL: 2881.5 ± 321.5W], peak force [P=0.974, CL: 2606.8 ± 286.6N; AEL: 2589.5 ± 275.6N] or peak velocity [P=0.588, CL: 1.2 ± 0.2m.s-1; AEL: 1.2 ± 0.2m.s-1], mean ± SD across the four sets for each condition). Vastus lateralis (P=0.560, CL: 133.1 ± 7.5% of normalised EMG [%]; AEL: 127.9 ± 1.4%), Bicep femoris (P= 0.126, CL: 142.3 ± 25.0%; AEL: 157.2 ± 24.2%) and Vastus medialis (P=0.887, CL: 140.1 ± 9.0%; AEL: 134.9 ± 5.5%) EMG was not significantly different between conditions. Gluteus maximus (P=0.090, CL: 136.8 ± 16.4%; AEL: 143.0 ± 12.0%) demonstrated tendencies towards greater activation during the concentric phase for the AEL condition. In conclusion, an acute AEL protocol did not enhance concentric phase kinematic variables above those in the CL condition despite a tendency for increased Gluteus maximus neuromuscular activation. This suggests that there would be no advantages over CL resistance exercise in achieving chronic strength adaptations. Future research employing well-controlled training programme interventions adopting both a battery of kinematic and physiological measures are required to substantiate this thesis.