Why do muscles hurt after training?

The exact biochemical cause of muscle soreness is not yet known, but that doesn't mean we don't know anything about it. We know, for example, that soreness typically occurs when you expose your body to a stress you are not used to, like trying a new exercise, workout or sport.

BackRead More

The soreness is thought to be tied to the same microtrauma which causes muscles adapt to training. This ties in with another observation that soreness is significantly worse after eccentric training (lengthening muscles under load) which includes things like lowering weights and running downhill, and is known to cause more microtrauma than other training styles.

Muscle pain isn’t always DOMS (delayed onset muscle soreness) either, as muscle soreness can also include cramps, injury and muscle damage. In this post, we are going to investigate various reasons why soreness can occur, and what you can be doing before, during, and after workouts to prevent or mitigate the damage, allowing you to train more frequently and keep progressing.

Training Too Hard

When you first start exercising, you’ll want to see results fast. Pushing your body through a new challenge in this way is what creates the environment for soreness to develop. As stated by the NHS, “sore muscles after physical activity, known as delayed onset muscle soreness (DOMS), can occur when you start a new exercise programme, change your exercise routine, or increase the duration or intensity of your regular workout.” Don’t chase pain as the only marker of progress though. While the adage of ‘no pain no gain’ can be useful for a motivational boost, it’s not exactly a hard and fast sports science rule – as you adapt to your training, the soreness will start to fade, but you’ll still be making big improvements.

The reality is that if you train too hard, and push your limits, you are going to feel it the next day. You should first focus on getting into a routine that works for you, and then gradually increase the intensity and duration of your workouts at a rate your body can keep up with.  

Inadequate Recovery

Oftentimes, the issue isn’t the workload itself, but rather not taking the proper steps following your workout to give your body everything it needs to repair and rebuild. If you want to minimise fatigue and train as frequently as possible,  recovery is everything.  

You can stop soreness in its tracks by using cold treatment immediately after your more intense workouts. This blunts your body’s inflammatory response, preventing the soreness before it begins, but, it comes at a cost. That same inflammatory response drives muscular adaptation, so if you choose to use this method, keep in mind that while your soreness levels will be reduced, so will your rate of improvement.

Another way to reduce the impact of DOMS is to perform a thorough warm down with some stretching and like cardiovascular activity. The famous collegiate coach Gary Winckler once said ‘Finish each workout feeling as you would like feel when you begin the next one’, which is sound advice to be mindful of.

Not Eating Properly

A balanced diet will ensure that you are getting the correct amount of nutrients in your body, which your muscles will use for fuel, repair and recovery. Eating antioxidant rich foods like vegetables and berries will help your body deal with the oxidative stress from training. Ensuring that you are getting enough fats and proteins will provide the building blocks for key biological structures, like muscle fibres and cell membranes.


Always ensure that you don't mistake injury for regular soreness. There may always be a desire to go beyond your goals and lift harder, run further, but if the pain feels sharp or unusually intense it’s a good idea to take a few days off to assess the damage. If it doesn’t improve, consult a physiotherapist. Training injuries are more common than you might think, and it can be tempting to push through the pain in the hope they will resolve themselves, but long term you will always make progress if you let yourself heal properly before pushing the pace once more.

Never miss a post!

Get DNAfit's latest content straight to your inbox

We'll send you a monthly blog round-up filled with all our latest posts, eBooks, and special offers.

Subscribe for DNAfit News