EMG-aktivitet och 6-RM styrka i bänkpress med stabila och ostabila underlag

[King Grub]

The purpose of the study was to compare six-repetition maximum (6-RM) loads and muscle activity in bench press on three surfaces, namely stable bench, balance cushion and Swiss ball. 16 healthy, resistance-trained males (age 22.5+/-2.0 years, stature 1.82+/-6.6 m, and body mass 82.0+/-7.8 kg) volunteered for three habituation/strength testing sessions, and one experimental session. In randomized order on the three surfaces, 6-RM strength and electromyographic activity of pectoralis major, deltoid anterior, biceps brachii, triceps brachii, rectus abdominis, oblique external and erector spinae were assed. Relative to stable bench, the 6-RM strength was ~93% for balance cushion (P<=0.001) and ~92% for Swiss ball (P=0.008); the pectoralis major EMG activity was ~90% using the balance cushion (P=0.080) and ~81% using Swiss ball (P=0.006); the triceps EMG was ~79% using the balance cushion (P=0.028) and ~69% using the Swiss ball (P=0.002). Relative to balance cushion, the EMG activity in pectoralis, triceps and erector spinae using Swiss ball was ~89% (P=0.016), ~88% (P=0.014) and ~80% (P=0.020), respectively. In rectus abdominis, the EMG activity relative to Swiss ball was ~69% using stable bench (P=0.042) and ~65% using the balance cushion (P=0.046). Similar EMG activities between stable and unstable surfaces were observed for deltoid anterior, biceps brachii and oblique external. In conclusion, stable bench press had greater 6-RM strength and triceps and pectoralis EMG activity compared to the unstable surfaces. These findings have implications for athletic training and rehabilitation, as they demonstrate an inferior effect of unstable surfaces on muscle activation of prime movers and strength in bench press. If an unstable surface in bench press is desirable, a balance cushion should be chosen instead of a Swiss ball.

Electromyographic activity and 6-RM strength in bench press on stable and unstable surfaces. Journal of Strength & Conditioning Research. 11 June 2012