Self-Managed Exercises, Fitness and Strength Training, and Multifidus Muscle Size in Elite Footballers

Abstract

Context: Low back pain (LBP) and lower limb injuries are common among Australian Football League (AFL) players. Smaller size of 1 key trunk muscle, the lumbar multifidus (MF), has been associated with LBP and injuries in footballers. The size of the MF muscle has been shown to be modifiable with supervised motor-control training programs. Among AFL players, supervised motor-control training has also been shown to reduce the incidence of lower limb injuries and was associated with increased player availability for games. However, the effectiveness of a self-managed MF exercise program is unknown.

Objective: To investigate the effect of self-managed exercises and fitness and strength training on MF muscle size in AFL players with or without current LBP.

Design: Cross-sectional study.

Setting: Professional AFL context.

Patients or other participants: Complete data were available for 242 players from 6 elite AFL clubs.

Intervention(s): Information related to the presence of LBP and history of injury was collected at the start of the preseason. At the end of the preseason, data were collected regarding performance of MF exercises as well as fitness and strength training. Ultrasound imaging of the MF muscle was conducted at the start and end of the preseason.

Main outcome measure(s): Size of the MF muscles.

Results: An interaction effect was found between performance of MF exercises and time (F = 13.89, P ≤ .001). Retention of MF muscle size was greatest in players who practiced the MF exercises during the preseason (F = 4.77, P = .03). Increased adherence to fitness and strength training was associated with retained MF muscle size over the preseason (F = 5.35, P = .02).

Conclusions: Increased adherence to a self-administered MF exercise program and to fitness and strength training was effective in maintaining the size of the MF muscle in the preseason.

Keywords: Australian Football League; independent exercise; lumbar muscles; motor-control training; ultrasound imaging.

Figures

Figure 1.

A, Ultrasound imaging of the multifidus muscle with the participant positioned prone and the transducer placed transversely over the relevant spinous process. B, Ultrasound image of the left and right multifidus muscles in transverse section at the L5 vertebral level. Arrows indicate the lateral borders of the muscle. Lamina indicates the hyperechoic vertebral lamina. Abbreviations: SP, “shadow of the tip” of the spinous process; ST, subcutaneous tissue.

Figure 2.

Cross-sectional area (CSA) of the multifidus (MF) muscle at the L5 vertebral level for MF muscle training and low back pain (LBP) groups during the preseason. Abbreviations: Time 1, start of preseason; Time 2, end of preseason. Note: Values are expressed as mean (cm2) and the error bars represent standard error. Mean CSA measurements are adjusted for age, height, and weight. The players who did MF training during the preseason did not have a decrease in MF muscle CSA as indicated by the overlapping error bars. Players with no MF muscle training had muscle decreases, and the LBP group had the biggest decrease.

Figure 3.

Cross-sectional area (CSA) of the multifidus (MF) muscle at the L5 vertebral level for fitness and strength training groups during the preseason. Abbreviations: Time 1, start of preseason; Time 2, end of preseason. Note: Values are expressed as mean (cm2) and the error bars represent standard error. Mean CSA measurements are adjusted for age, height, and weight. Daily fitness and strength training contributed to less reduction in MF muscle CSA than training only a few times a week.