Muscle Endurance Tests Can Detect Early Stages of Multiple Sclerosis

Now, researchers from Tel Aviv University have discovered that specific laboratory tests for leg muscle endurance and gait – the pattern of movement during walking or running – are highly effective in identifying mobility deficiencies at the early stages of multiple sclerosis. These deficits are difficult to discover during regular neurological examinations.

Reduced muscle endurance may be one of the earliest indicators of MS and is a common complaint among patients, but it is hard to detect, according to lead author, Dr. Alon Kalron. In order to quantify muscle fatigue, the researchers conducted a study that included 52 patients in the early stage of MS, and a control group of 28 healthy subjects.

Participants were examined using a device known as an isokinetic dynamometer, an instrument used for measuring lower limb muscle strength and endurance. They were asked to attempt to bend or straighten a knee to exert maximum effort and maintain this position for 30 seconds. Muscle fatigue was calculated by measuring the decline in muscle strength during that period. On average, those in the early stages of MS were not able to maintain their strength – they only demonstrated 40 percent less endurance when compared to the healthy control group.

Additionally, patients’ gat was observed for factors such as how far a patient spreads his legs while walking, the length of their steps, and symmetry of movement. By examining walking patterns, the researchers discovered specific cases of abnormalities in the MS group. According to Dr. Kalron, patients in the early stages of MS “tend to walk with a wider base, because with your legs further apart helps to improve stability. It’s probably a compensation strategy due to the lower muscle endurance.” The individuals in the MS group also displayed a slower walking speed, an asymmetrical pattern of movement and shorter steps.

Physicians should be made aware of possible gait and lower limb muscle deficits very early in the disease process, especially since minor impairments are difficult to find through the use of standard neurological testing. Dr. Kalron suggests "The downside of detecting such deficits using advanced instruments is offset by the positive potential of early intervention programs. If we find the abnormalities earlier, then we can start intervention programs when they have a chance to benefit the most." Physical therapy programs and fitness can help MS patients maintain higher levels of muscle endurance and improve balance, while holding off the fatigue that is typically associated with the disease.