|The Weight Belt Controversy
By Christopher C. Frankel and Len Kravitz, Ph.D.
Athletes and fitness enthusiasts sometimes employ the use of external support belts to provide a level of protection against low back injury as resistance training sessions progress in intensity and complexity of movement. Indeed,weightlifting belts have been widely used in resistance exercise, assumingly providing a safer lifting environment for the lifter (Bauer, Fry, & Carter, 1999). These support belts are alleged to protect the low back from injury and to allow for a greater overload stimulus on the lower-body musculature during exercises such as squats and deadlifts. The assistance and/or protection provided by a support belt during exercise may be a result of increased abdominal pressure (IAP), feedback to the exerciser on body position, reduced compressive and shear forces on the spine, and restricted torso movement (Smith et al., 1996).
However, recent research has questioned the validity of using these belts to reduce the stress imposed on the regionalskeletal system (thoracic, lumbar and sacral spine) and the muscles acting posteriorly to these structures, primarily theerector spinae (Bauer, Fry & Carter, 1999). Do weightlifting belts reduce the risk of injury to the low back during strength training? This article will examine research related to the use of lumbosacral support belts (LSS) and their effectiveness in providing assistance and/or injury prevention during lifting exercises, primarily squatting and deadlift-type movements.
Research on the Use of Belts During Lifting
The affect of increased IAP during lifting has been theorized to aid in supporting the spine during lifting. An increase in IAP is assumed to provide a mechanism of anterior support for the spine during lifting, decreasing the load to the spine and protecting the vertebrae, discs, and articulating muscles. However, even when rigid weightlifting belts were studied, as opposed to softer belts used in industrial settings, some studies demonstrate increases in IAP by as much as15% to 40%, whereas other investigators have shown no consistent effect on IAP (Smith et al. 1996).
Electromyography (EMG) is a clinical method used to determine muscle activity during lifting exercises. This method is based on the assumption that changes in electrical impulses detected by sensors attached to the skin overlaying the muscles reflect changes in muscle recruitment and activity. In a recent study, Bauer, Fry and Carter (1999) investigated the EMG activity of the erector spinae muscles during high bar squats. Ten men with weightlifting experience performed two sets of three repetitions: the first set with and the second set without a weight belt. The load used in this experiment equaled 60% of each subjects 1RM. Findings indicated that the average erector spinae activity was greater in the lumbar region of the spine while wearing the belt. The hypothesis of the study stated if weight belts provide additional support to the spine during squatting there should be a decrease in the activity of the back extensor muscles. This lead the authors to conclude that the weight belt did not provide the biomechanical change expected to minimize the risk of low back injury.
An earlier study by Smith et al. (1996) looked at the combined effect of a LSS belt and abdominal strength in women on functional lifting ability. The activity involved moving a weighted box from floor to waist height and back to the floor with the load increasing each repetition. LSS belts were found to be effective in improving lifting ability in the female subjects by an average of 1 kilogram (kg). While statistically significant, the authors cautioned that a kg increase is functionally small and not sufficient for them advocate the use of belts for increasing lifting capacity. Interestingly, it was also shown that the maximum weight lifted varied with abdominal muscle strength. The women with strong abdominal muscles lifted significantly more than women with weak abdominals.
The effect of belt use on muscle fatigue and isometric strength has also been studied during isolated back extension movements and functional lifting in industrial settings. Ciriello and Snook (1995) found no significant differences between belt and no-belt conditions in isokinetic endurance, rating of perceived exertion and EMG activity in industrial workers after prolonged lifting. Similarly, Reyna et al. (1995) found no differences in isometric strength measured at several different angles of back extension when wearing and not wearing a belt. It was also found that the use of a belt provided no advantage in functional capacity evaluated by lifting weighted canisters from various levels. These studies illustrate a general finding in the literature that LSS belts provided no advantage in lumbar strength, endurance, or functional lifting capacity under industrial type, prolonged lifting activities.
Evaluating Research and Making Decisions
As a fitness professional you have to be able to advise your clients based on scientific evidence and experience in the field. A valuable skill is to be able to identify limitations in research. The conditions in a laboratory can be quite different than in the context of a training session. Limitations to consider when evaluating the research in this area include the following:
EMG methods are controversial themselves for evaluating muscle activity, especially during dynamic contractions.
Isolation movements such as stabilized back extensions are different from functional closed chain movements (squat, deadlift) and generalizations may not be appropriate.
Industrial settings where loads are lower and durations are substantially longer (4 hours or more) do not replicate the conditions in the gym.
Some clients may find the use of a weightlifting belt helpful in maintaining proper form during exercise. However, this is not a stand-alone solution or preventive measure. Teaching your clients' proper form and prescribing the appropriate exercises and loads appears to be the best primary intervention to reduce the risk of injury during exercise. However, a lumbar belt may provide a beneficial effect when performing maximal lifts, such as in power lifting. Finally, it is important for the trainer to realize that there is a complex interaction of the muscles, such as the abdominals (especially the obliques and transverse abdominals) and other sensory influences (such as proprioception and kinesthetic awareness) when doing lifting tasks that should always be considered when designing safe and effective exercise
Bauer, J.A., Fry, A., and Carter, C. The use of Lumbar-Supporting Weight Belts While Performing Squats: Erector Spinae Electromyographic Activity.Journal of Strength and Conditioning Research. 1999;13: 384-388.
Ciriello, V.M., and Snook, S.H. The Effect of Back Belts on Lumbar Muscle Fatigue. Spine 1995;20;1271-1278.
Reyna, J.R., Leggett, S.H., Kenny, K., Holmes, B., and Mooney, V. The Effect of Lumbar Belts on Isolated Lumbar Muscle. Spine 1995;20:68-73.
Smith, E.B., Rasmussen, A.A., Lechner, D.E., Grossmen, M.R., Qunitana, J.B., and Grubbs, B.L. The Effects of Lumbosacral Support Belts and Abdominal Muscles Strength on Functional Lifting Ability in Healthy Women. Spine 1996;21: 356-366.