Back extension (BE) is a strength exercise for training the dorsal trunk and hip muscles. To optimise training recommendations that avoid overloading and possible injury, the aim of this study was to determine the loading conditions and the influence of different execution forms of BE on spine, hip and knee ranges of motion (RoMs), joint moments and muscle activity.
The kinematics, kinetics and muscle activity (EMG) of two execution types (BEh: dynamic hip, BEs: dynamic spine) and two versions (one-legged and two-legged) of BE were measured in 16 subjects. RoMs and external joint moments were calculated using an inverse dynamics approach and analysed with a linear mixed model.
Although lumbar spine flexion was observed in both execution types, thoracic spine flexion predominantly occurred during BEs, whereas thoracic spine extension was observed during BEh. Larger maximal back and hip moments were observed for BEh than for BEs. The activity of the dorsal back and hip muscles, as observed using EMG, was increased for one-legged executions.
To strengthen the hips and lower back, BEh seem to be more efficient due to the higher moments, with higher or similar RoMs in the hip and lower back. One-legged BEs seem to provide an effective training for the hamstrings and hip regions without subjecting the spine to excessive loading, possibly promoting this as an effective exercise during training and rehabilitation.
Müller R. Fitness Centers: Injuries and Discomforts During Training. Federal Institute for Injury Prevention. Bern: BFU; 1999.
Hansen JW. Postoperative management in lumbar disc protrusions. I. Indications, method and results. II. Follow-up on a trained and an untrained group of patients. Acta Orthop Scand. 1964;35 Suppl 71:3–47. CrossRef
Contreras BM, Cronin JB, Schoenfeld BJ, Nates RJ, Tiryaki Sonmez G. Are All Hip extension exercises created equal? Strength Cond J. 2013;35(2):17–22. CrossRef
Haff GG, Triplett NT. Essentials of Strength Training and Conditioning. 4th ed. Human kinetics 2015.
Dettwyler M, Stacoff A, Stüssi E. Static in situ calibration of statically overdetermined ground reaction force measurement platforms. In: Milburn P, Wilson B, Yanai T, editors. XIXth international congress of biomechanics. Dunedin, New Zealand: University of Otago; 2003. p. 88.
Zatsiorsky VM. Kinetics of human motion: human kinetics. 2002.
Gander W, Hrebicek J. Solving problems in scientific computing using Maple and Matlab®. Berlin: Springer Science & Business Media; 2011.
Konrad P. The ABC of EMG: A Practical Introduction to Kinesiological Electromyography. Scottsdale, AZ; 2006.
Farris DJ, Lichtwark GA, Brown NAT, Cresswell AG. Deconstructing the power resistance relationship for squats: A joint-level analysis. Scand J Med Sci Sports. 2016;26:774–81. doi: 10.1111/sms.12508.
- Loading conditions in the spine, hip and knee during different executions of back extension exercises
William R. Taylor
- BioMed Central
Neu im Fachgebiet Orthopädie und Unfallchirurgie
Mail Icon II