Surface electromyography excitation in barbell vs. kettlebell overhead press prime movers and stabilizer muscles

Purpose The current study compared the muscle excitation of the primary and stabilizer muscles during standing overhead press performed with either the barbell (barbell-OHP) or the kettlebells (kettlebell-OHP), using surface electromyography. Methods Ten male StrongFirst-certified instructors in the OHP, performed either the barbell-OHP or the kettlebell-OHP in a non-fatiguing set with an external load of 8-RM. Muscle excitation of the anterior deltoid, lateral deltoid, posterior deltoid, upper trapezius, triceps brachii, flexor carpi ulnaris, latissimus dorsi, rectus abdominis, external oblique, erector spinae and gluteus maximus was recorded during both the descending and the ascending phase. Results During the ascending phase, the kettlebell-OHP showed superior excitation of the flexor carpi ulnaris (p < 0.01, ES = 1.90), erector spinae (p = 0.04, ES = 0.71) and gluteus maximus (p < 0.01, ES = 1.00) while in the descending phase, the kettlebell-OHP exhibited superior excitation of the anterior deltoid (p = 0.04, ES = 0.69), upper trapezius (p = 0.04, ES = 0.69), flexor carpi ulnaris (p < 0.01, ES = 4.04) and erector spinae (p = 0.04, ES = 0.70). No between-exercise difference was observed for the lateral deltoid, posterior deltoid, triceps brachii, latissimus dorsi, rectus abdominis and external oblique. Conclusion The kettlebell-OHP may be more effective than the barbell-OHP in recruiting both primary movers and stabilizers, making it a potentially valuable addition to training for increased strength and rehabilitation benefits. However, the different barbell peculiarities make both resistances suitable for inclusion in a training routine.