Should You Exercise with Sore Muscles?

We all know the post-workout pain of sore muscles, but should you delay further training until the pain subsides? Will pushing through the pain delay recovery or cause further damage? And, if pain indicates damage, does post-workout pain mean you’ve done things right or very wrong?!

These are very common questions asked by athletes at all levels. Dr Samantha Burrows, Medical Director at London Doctors Clinic, is a GP with a special interest in sports and exercise, having graduated with an MSc in Sports and Exercise Medicine. We put her expertise in sports and exercise medicine to the test, asking her these pertinent questions!

Why are your muscles sore after exercising?

There are two main types of pain commonly experienced after exercising. It’s important to recognise the difference between the two, as they each have different managements.

The first, is the sharp, cramping pain of a lactic acid build-up, often experienced after intense episodes of high energy activities, such as sprinting.

(1) Lactic Acid Build-Up

Our body has two ways of releasing energy for exercise: aerobic and anaerobic respiration. The former is preferential and most efficient, although requires a steady sufficient supply of oxygen, delivered by the blood. The more you train, the more efficient your body becomes at meeting this oxygen requirement, by means of a strong cardiovascular system.

In times of intense exercise with insufficient oxygen available, the body can also perform the latter method of energy release (anaerobic respiration) for a limited period of up to around 3 minutes – allowing us to step up our well-paced run to an all-out sprint! The only downside with this method of energy release is the build-up of lactic acid in the muscles.

Have you ever wondered why, after a race, you’re encouraged to keep walking or moving? This is to slowly release the lactic acid that has likely accumulated in your muscles in those final metres of the race. If this lactic acid build-up is too high, or not properly ‘walked out’, it can lead to the intense cramping pain sometimes experienced by athletes, post-race (relieved by light exercise and stretching).
However, lactic acid is only responsible for pain immediately after exercise – if you’re still in pain hours later, or the next day, it’s more likely to be due to muscle damage.

(2) DOMS

Delayed onset muscle soreness (or DOMS for short), is pain and stiffness experienced in the muscles after strenuous exercise. Such pain usually becoming evident between 8-10 hours’ post-exercise and peaks in severity at 24-48 hours’ post-exercise. It more often occurs after either strenuous exercise (such as lifting weights heavier than usual), or performing exercises that your body is simply not used to (such as an intense running session after a long period off).

DOMS pain is usually noticed when trying to use that muscle the next day – for example, trying to climb stairs the day after an intense run or squat workout. The type of exercise which especially results in DOMS is eccentric exercise, which involves the muscle fibres being overstretched. This is by the elongation of muscle, under a tension (such as your body weight) greater than the force generated by the muscles. So, if you’re used to running at a certain pace, your muscle fibres will be used to this level of stretch, but if you change something about your standard run (such as increase your weight by means of a heavy rucksack), then this will disrupt the fine balance between muscle elongation and force, resulting in an eccentric exercise.

The mechanism behind DOMS is disputed, with various hypotheses still being debated, such as the disruption of connective tissue around the muscle, or the uncontrolled movement of calcium ions into the muscle cells, although it is thought that many factors may contribute to the overall effect of pain and soreness.

Dealing with DOMS

One thing you can do to speed up recovery, is ensure you consume plenty of protein – ideally by means of protein-high meals, or alternatively from protein shakes – to ensure efficient re-building of these damaged muscle fibres. This cycle of eccentric workout coupled with a high protein intake is practised by athletes and body-builders alike, as a technique to increase muscle mass – in which case, post-work-out pain is an indication that the cycle is working.

As with everything, DOMS gets better in time, and usually doesn’t need any treatment. If post-workout pain is impacting your everyday routine, then anti-inflammatory medications such as Ibuprofen can help relieve the pain and a hot bath may also help take the edge off the pain (albeit temporarily). There’s little evidence to support the use of massage therapy to reduce post-workout muscle pain.

And don’t forget to stretch! The best way of dealing with DOMS, is not to develop it in the first place! Thoroughly stretching both before and after working-out will significantly decrease your chance of developing muscle soreness afterwards.

So, down to the question at the tip of every athlete’s tongue: “Can I still work out, while my muscles are recovering?”

As for working out, this depends on the severity of the pain. In some cases, you will physically not be able to do further exercise for a couple of days – ever got stuck trying to climb the stairs with wobbly legs after a super-intense leg work-out?! Better to take the lift, at least for a day or two, for risk of falling and further damaging yourself!

This is where the importance of rotating your types of training comes in. You should focus your next workout on a different muscle-group, while you give the previous muscle-group time to heal, hence athletes’ references to ‘leg day’ or ‘arms day’.

For good all-round fitness, rotating different activities such as tennis (a more arm-intense sport) and cycling (more leg-focussed), or swimming (a whole body workout) is perfect for covering all your different muscle groups, and allowing one group to recover while training another.

Certain exercises will further exacerbate the muscle soreness, which should be avoided for a few days until the DOMS-pain subsides. Squats, for example, are a no-go after intense eccentric workout of the quads and glutes, as they will make this pain worse at a time when the muscle should be recovering. Don’t try squatting the day after an intense spinning class, if your leg muscles are still recovering, as aside from being provoking further unpleasant pain, limiting your ability to perform this activity effectively, over-using these already-damaged muscle fibres may result in prolonged pain and delayed recovery.

At What Point is Post-Workout Soreness Indicative of Something More Sinister?

If you’re experiencing symptoms of inflammation and swelling, alongside your standard DOMS-related pain, then there’s a chance you have sustained some kind of injury to the muscle, tendon or ligaments involved in your work-out. If this is the case, it’s best to stop exercising before you’ve seen a doctor, who is able to assess for injury. Muscle soreness generally lasts a maximum of 3 days after exercise, so pain persisting longer than this could also be a cause for concern.

Aside from these mechanical injuries, such as tendon tears and ligament overstretching, one important condition to be wary of is rhabdomyolysis, or ‘rhabdo’ for short. The initial symptoms can be subtle, but the overall effect can be devastating, so it’s worth brushing up on your medical knowledge here, to quickly recognise the tell-tale signs.

Rhabdomyolysis - meaning the break-down of skeletal muscle - can occur after a crush-injury, or after strenuous exercise in athletes. The condition is characterised by muscle pain and tenderness, as well as weakness and swelling of the muscle group.

This muscle breakdown releases an outpouring of chemicals from the muscles, which then, in turn, exert a detrimental effect on the kidneys, resulting in symptoms such as low urine output and dark-coloured urine. Systemic symptoms are also often noted, such as confusion, nausea, vomiting and general malaise (feeling unwell).

In the most extreme cases, a fasciotomy is required - a surgical procedure in which the skin on top of the muscle is cut open, allowing for inevitable muscle swelling while relieving pressure on important internal structures within the limb such as blood vessels and nerves. In severe swelling of the legs, this increased pressure within the muscle compartment can compress the essential blood vessels and compromise the blood supply, putting the limb at risk of ischaemia and even tissue death.

Overall, muscle pain is often just part and parcel of intense training regimens. That said, it’s worth being aware of what is normal for delayed-onset muscle soreness, what isn’t and what could indicate injury or conditions such as rhabdo. Additionally, instead of further exercising with sore muscles, it’s far better to change up your weekly exercise routines and incorporate different muscles groups on different days, to prevent further exacerbating post-workout pain!

By Dr Samantha Burrows