Why are my muscles sore after a workout?

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Why Do My Muscles Get Sore After A Workout?

Every wonder why we get sore after a workout? Is it even good for us that it hurts to roll out of bed, brush our hair and even sit on a chair days after a workout? Muscle soreness is known as ‘delayed onset muscle soreness’ or ‘DOMS’ and not only can it begin 12-24 hours after exercise, the pain is often worse 24-72 hours later!

There are multiple factors that contribute to experiencing DOMS. High tensile forces are experienced during eccentric contractions of an exercise. Eccentric contractions are when the muscle fibres are simultaneously contracting and lengthening – for example, the lowering phase of a squat or bench press, downhill running or plyometrics. This can lead to micro-tears and disruption of the muscle fibre and connective tissue structural proteins. This stimulates the inflammatory response which produces swelling. DOMS or muscle pain is what we feel as a side effect of this repair process. The intensity and duration of exercise are also important factors in the onset of muscle soreness.


Bench photoSquat photo



Image: Displaying Eccentric Component of Barbell Back Squat (Left) (1) and Bench Press (Right) (2)

Now I know what you’re thinking. This is terrible for me right? Surely this can’t be a good thing particularly if I’m ‘tearing’ my muscles? The process of DOMS is a natural and normal part of how the muscles respond to activity, particularly if you’ve never done the exercise before. During this repair process, the muscle fibres regenerate to be resistant to further stress. In other words, your muscles begin to adapt. This is why you find that the severity of DOMS reduces as you do regular workouts. Alternatively, you’ll experience an increase in the severity of DOMS when you learn a new exercise, change the exercises in your program or start exercising for the first time. Please note that DOMS is different to acute soreness. Acute soreness is the pain that develops during the exercise and signals a problem: such as the exercise being too intense or incorrect technique.

So what can you do if you experience DOMS? Initially, DOMS should be treated with ‘active’ rest such as cycling or walking (3, 4). Intense exercise of the affected muscle groups should be avoided. This is due to the reduction in joint ROM and the reduced capacity of your muscles to cope with shock absorption (4). Alterations in muscle recruitment patterns can also occur therefore can causes too much stress on the muscle ligaments and tendons. Research studies (3, 5) have shown that gentle massage and pressure garments help reduce the severity and duration of DOMS. However deep tissue massage and excessive muscle stretching should be avoided in the first 24 hours to allow the muscle fibres to repair and heal.

flowchart pic

Flow chart: Process of Delayed Onset of Muscle Soreness



Flow chart: Process of Delayed Onset of Muscle Soreness

Joanne Hausler

Certified Personal Trainer




  1. Lefferts, B. (2015), 4.1 Barbell Back Squat (5reps) [Photograph]. Retrieved 8 March, 2016, from American Fitness Magazine, September/October Issue, Wonder Women. http://www.nasm.org/american-fitness-magazine/issues/september-october-issue/wonder-women-workout
  2. Christian. (2014), Close Grip Bench Press for Tricep Workout [Photograph]. Retrieved 8 March, 2016, from Build Muscle 101. http://build-muscle-101.com/close-grip-bench-press/
  3. Zainuddin, Z. Newton, M. Sacco, P. et al (2005). Effects of Massage on Delayed-Onset Muscle Soreness, Swelling, and Recovery of Muscle Function. Journal of Athletic Training, 40(3), 174-180. Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1250256/
  4. Cheubg, K. Hume, P. A. Maxwell, L. (2003). Delayed Onset Muscle Soreness. Treatment Strategies and Performance Factors. Sports Medicine 33(2), 145-164. doi 10.2165/00007256-200333020-00005
  5. Hill, J. Howatson, G. van Someren, K. et al (2014). Compression Garments and Recovery from Exercise-Induced Muscle Damage: A Meta-Analysis. British Journal of Sports Medicine 48(18), 1340-6. doi: 10.1136/bjsports-2013-092456