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A common barrier while attempting to persevere through an intensive long-term exercise program is having to deal with muscle soreness afterwards, which is also known as delayed onset muscle soreness (DOMS). Unlike the acute soreness that develops during the actual activity, delayed soreness becomes prominent approximately 24 hours after exercising, and is positively correlated to the duration and intensity level exerted. Although various studies have been performed regarding DOMS, the ultimate cause of the symptom is still unknown. However, there has not been any report of DOMS posing as a permanent threat to the body.

Most people unfamiliar with DOMS are often deceived into believing that there is a correlation between pain and injury, where continued exercise while experiencing DOMS leads to further injuries. As a result, many simply stop their exercise routines and turn to treatments such as taking a hot shower or using heat pads to alleviate the pain, which may take up to a week after the initial symptom. However, by that time, your muscles will have decreased its ability to adapt to the intensity level of your routine, and that hour of intensive exercise you performed earlier becomes a waste.

The main cause of DOMS still remains unknown, but many studies have investigated the mechanisms involved and suggested possible explanations. First, studies performed by Armstrong demonstrate that high intensity exercise result in greater metabolic waste, such as lactic acid, which may influence the calcium concentration gradient within the muscle tissue and stimulate neuron activity to increase pain sensation (1). Hough suggests that DOMS is related to the rate and force of muscle contraction during strenuous exercise, which leads to structural damage (2). Supporting Hough’s findings, Kumazawa et al. also suggest that elevated temperature plays a role in damaging muscle structure and promotes necrosis of muscle fibres and connective tissues (3). In brief, there is no main cause of DOMS. It is most likely caused by a combination of various factors, which leads to the difficulty in developing a treatment that can efficiently eliminate DOMS.

There are various treatments for DOMS such as having a proper cool-down period after exercising, taking a hot shower, or wearing compression sleeves. However, continuing to exercise while experiencing DOMS is actually the only proven way to effectively eliminate DOMS. According to Armstrong, one the reasons why continued exercise can reduce DOMS is its ability to decrease the rate of muscle fibre necrosis (1). There has also been evidence for the reduction of exercise plasma enzymes, which indicates that continued exercising can reduce muscle fibre injuries (4). Lastly, lysosomal enzyme levels have been shown to decrease while exercising with DOMS, resulting in the reduction of the rate of muscle cell death (5). Therefore, although it may be difficult to motivate yourself while experiencing DOMS, the most effective way to treat DOMS is actually to continue exercising until your muscles adapt to it.

-Bailey Lei

References

1. Armstrong, R.B. Mechanisms of exercise-induced delayed onset muscular soreness: a brief review. Med. Sci. Sports Exerc. 16(6): 529-538, 1984.

2. Hough, T. Ergographic studies in neuro-muscular fatigue. Am. J. Physiol. 5:240-266, 1901.

3. Kumazawa, T. and K. Mitzumura. Thin-fibre receptors responding to mechanical, chemical, and thermal stimulation in the skeletal muscle of the dog. J. Physiol. (Lond.) 273: 179-194, 1977.

4. Schwane, J.A. and R.B. Armstrong. Effect of training on skeletal muscle injury from downhill running in rats. J. Appl. Physiol. 55: 969-975, 1983.

5. Vihko, V., A. Salaminen, and J. Rantamaki. Exhaustive exercise, endurance training, and acid hydrolase activity in skeletal muscle. J. Appl. Physio. 47: 43-50, 1979.