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  • Writer's pictureTrang Nguyen

6 reasons runners need to train strength rather than endurance in the gym

Runners are endurance athletes. Yet why am I always harping on about developing strength & lifting heavy? Runners don’t want to get big or lift heavy, the sport is endurance running goddammit! Well, this is why…

The role of Strength and Conditioning (S&C) training for runners should be to fulfil 3 different purposes:

1. Increase the capacity of the body’s tissues to tolerate running loads

Ground reaction forces on the body are about 3-4x one’s bodyweight when they run. Some muscles are exposed to even larger forces, particularly the calves that take on 6-8x bodyweight in forces, and quads 4-6x. Strength training increases the stability of your joints, the strength of your muscles and connective tissues and the bone mineral density of your bones. As a result, the body’s capacity to tolerate these running loads will be improved and you will reduce your risk of overuse injuries.

2. Increase ability to produce force

Running speed is a combination of step length and step frequency. If a runner has stronger muscles, then they will be able to produce more force with each step and take bigger steps without actually using more energy. This means the stronger runner will be able to run at the same pace using less energy or run faster using the same amount of energy. Between two runners identical in all fitness levels except different leg strength, the stronger runner will be more economical and be able to run faster for longer.

3. Increase your longevity as a runner

Age-related changes cause reduced muscle mass, reduced force output, reduced tendon stiffness (Springy-ness) and poorer joint stability. Partaking in strength training will preserve the musculoskeletal system and its function for running and will allow runners to continue running into their master years.

See Gene Dykes to the right, an incredible example of a healthy, functioning master runner. Although Gene himself never did strength training himself, he represents the minority with epic genes, and the majority of people will need a bit more work to be running 100km weeks at 70 years old!

If these are the objectives for S&C training in runners, then the training programming must be planned in a way that facilitates those adaptations, and align with helping the runner achieve their goals both immediately and in the long term.

This is where heavy training comes in. Heavy training refers to lifting a weight that is heavy enough for 1-6 rep max (Maximum number of reps that can be forcibly produced against that resistance). Even for endurance athletes, lifting these weights are beneficial for these 6 reasons:

  1. It’s heavy strength training for low reps that achieves muscular strength AND tendon stiffness (Springy-ness). It’s been shown that light training for higher reps achieves muscular strength, BUT NOT tendon stiffness. And in runners, it’s often the tendons that fail to keep up with running demands more than the muscles.

  2. Runners often don’t want excessive muscle mass. It’s actually lighter weight for higher reps (5 or more) that create ‘the pump’ (Metabolic stress), leading to bigger muscles! Research shows that heavier weights for low reps achieve strength with proportionately less muscle size increase, known as relative strength.

  3. The literature supports heavy training for low reps (Up to 6RM) for injury rehab. So for any injured runner in the Physiotherapy clinic, I aim to get them to that standard of strength in the late stages of rehab. Even if you’re not already injured, that’s even more reason to train heavy. Don’t be reactive, be proactive!

  4. Higher rep training (More than 5 reps) means more training volume. Because this type of training is done with a relatively lighter weight, rest breaks are often reduced compared to heavy weight, low rep training. This leads to increased metabolic stress and central nervous system fatigue due to the increased overall workload. As a result, the runner doing light weight for high reps may be MORE fatigued than when doing high weight for low reps, impacting subsequent running training sessions. This is not ideal since the strength training is only meant to complement the running, not take away from it.

  5. There is no evidence that strength training is detrimental to endurance performance. Research has shown that after moderate-elite runners partook in a 16-week strength program, there were many physiological benefits that supported performance improvements, without ANY performance impediments.

  6. The one best way to improve running endurance… Is to run and get the km’s in the legs. Runners are already good at that. The idea of strength training is to target physical improvements in ways that running does not allow… Including pure strength against high resistance, which allows those adaptations to the bones, muscles, connective tissues for both performance and injury management.

This is the form of training that is optimal for the athletic development of runners. However, other variables also need to be taken into consideration, including the athlete’s readiness for the training, experience in the gym, injury history, goals and more, so it never looks the same from one athlete to the next.

If you’re unsure and want to find out what the best form of training is for you to optimize your athletic potential, then shoot me an email at I’m always happy to help out!


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