“But I don’t want to get ‘bulky’…”
Whether runners don’t want larger muscles due to fear of slowed performance or personal appearance preferences, this is a common hesitation.
It is also a common misunderstanding. Our stance is that runners should not only strength train regularly, but work up to lifting heavier weights with less repetitions. That is, of course, when they’re ready to do so safely.
For most runners, the 1st priority is to establish a general strength training routine that will help decrease muscular strength imbalances. Those imbalances can lead to common injuries.
Once that is established and being maintained, the next step is to begin lifting for strength gains. That means heavier weights (≥ 85% 1-RM), less repetitions (≤ 6), and 2 – 5 minute rest intervals between.
Let's talk about why! Lifting lighter weights for more reps leads to muscular endurance gains (think "10 - 12 crunches for 2 - 3 sets).
Most of the time endurance athletes are getting muscular endurance gains through their endurance activities. Hills, high volumes of running, and long runs are a few examples of how we can gain muscular endurance through running.
That is why it is great if an athlete can work up to lifting heavier loads. Heavy lifting in particular leads to gains in muscular strength. Muscular strength can lead to higher ground force being placed with each stride. That means covering more distance with less effort. What runner doesn't want that?
A common concern is that lifting will cause an athlete to gain so much mass that their performance is negatively effected. Let's break it down!
Will muscular size increase from regular heavy lifting?
More than likely.
Will muscular size increase as a hypertrophy-focused athlete’s would?
Because runners are prioritizing RUNNING.
Most runners are training 3 – 7 times per week. Which means long durations of low intensity running that leads to increased muscular and cardiovascular endurance.
On the contrary, hypertrophy-focused athletes (ex: bodybuilders) are programming their “cardio” workouts, like hypertrophy-focused athletes. We are talking less volume and higher intensity. The goal simply isn't the same.
Exercise science is always evolving. Here is what we can take away from the most current research:
The running motion places a repetitive load of up to 3x bodyweight on each leg (130 lb. athlete = up to 390 lbs.)
Fewer exercises, repetitions, and sets with heavier weight-loads recruit muscle fibers that generate higher amounts of force.
Higher ground force production = faster, more efficient running.
To put it simply, strength training in general and strength training with heavier loads both are more likely to INCREASE performance than HARM it.
Anyone who wants to run without injury and to the best of their ability should strength train. Anyone who strength trains should add a logical progression, and for runners we believe that means lifting heavy weights for strength.
References and Further Reading:
American College of Sports Medicine (2018). ACSM’s Guidelines for Exercise Testing and Prescription 10thed.).
Baechle, T.R. & Earle, R.W. (2008). Essentials of Strength Training and Conditioning (3rd ed.). Champaign, Ill.: Human Kinetics