Runners: can leg training help prevent back pain?

If you’ve never suffered from low back pain, consider yourself lucky. Forty-nine percent of the UK population reports back pain that lasts at least 24 hours at some point each year, and 4 out of 5 adults experiencing back pain at some point in their life. This all comes at a cost; in the UK alone, this is estimated at several £billion per year through loss of productivity and absenteeism from work. For athletes such as runners and cyclists, the cost is in missed training days, missed competitions, and generally getting frustrated. After all, while you can ‘train around’ other injuries, a back injury is very debilitating, and light activity and movement is about all you can manage!

Given these facts, preventing back pain from recurring is extremely desirable. Studies show that doing nothing at all following an episode of back pain is NOT a good route to recovery – instead the rapid resumption of normal activity is now recommended by medical practitioners. Core strengthening work, targeting the muscles of the lower back and deep abdominal muscles is also recommended. The theory is that a stronger core helps to stabilise the spine, preventing sudden stresses on the spinal joints and ligaments, which can cause back pain. However, some fascinating  recent research by Singapore scientists on runners with chronic lower back pain suggests that strengthening the lower limbs (legs) could also be an effective way to prevent back pain  [Med Sci Sports Exerc. 2017 Dec;49(12):2374-2384].

The research

In this study, 84 recreational runners with chronic lower back pain were allocated to three exercise groups. These groups were:

• *Core stability (spinal stabilisation) strengthening exercises.
• *Lower back muscle (erector spinae) strengthening exercises.
• *Lower limb (leg) strengthening exercises

All the runners performed regular sessions to strengthen these muscles for a period of eight weeks and were assessed for levels of self-rated pain, running capability, lower limb strength, back muscle function, and running gait (stride length etc) before the intervention then again halfway through and immediately following the intervention. The results from the three groups were then compared. The researchers also tracked the runners over a longer period of time (three and six months) to see how long any benefits lasted.

The findings

When the self-reported levels of pain were assessed (using a standardised pain scale) after the intervention, all three groups reported a significant improvement (reduction in pain) of running-induced pain of around the same magnitude. However, in terms of functional ability – ie the ability to run efficiently – the lower limb strengthening group improved significantly, whereas there was no improvement in either of the other two training groups. The lower limb training group also experienced other benefits considered advantageous for runners, namely increased stride length and improved knee extension strength. And while they didn’t do any specific lower back training, the lower limb group experienced the same gains in lower back strength as the other two groups.

Sports Performance Bulletin verdict

This research is fascinating because it suggests that strength training the legs could be as effective as core and lower-back strengthening in helping runners tackle chronic lower back pain – while at the same time improving running functionality (eg stride length and running gait). This is just one study though, so it’s too soon to recommend ditching core and back strengthening work, which are known to help combat back pain. However, what it does suggest is that runners with chronic back pain should at least consider adding some leg strengthening training to their core/lower back work.

Implications for runners

• If you suffer from chronic lower back pain, consider adding in some leg strengthening exercises into your core training routine.
• Stick to simple exercises such as leg press, lunges, calf raises etc. The squat is also an effective exercise for strength training but it needs to be executed with meticulous form to ensure that any back pain isn’t exacerbated.
• With all exercises, start light and build up resistance only as long as your form remains strict.
• It is recommended that you seek professional advice from a physiotherapist prior to beginning a leg strengthening programme; he/she can advise on the most suitable exercises and rate of progression.