Many high level and recreational runners avoid weight training due to fear of building muscle or bulk which may be detrimental to their performance. On the surface this argument makes sense because a larger runner would have to expend more resources (fuel, oxygen) at at given speed and distance. One of the first flaws in the argument is the difference between strength development and muscle growth or hypertrophy following resistance training. While strength gains occur consistently with well planned programs, hypertrophy may or may not occur depending on many training and participant factors. In the case of a runner, their caloric balance (in vs. out) and genetic make up makes hypertrophy or mass less likely after a strength training program. Two recent studies demonstrate moderate to strenuous weight training in this population can produce performance benefits without changes in a runner’s body weight.
Storen and colleagues examined the impact of a strength training program on well trained male and female runners (Med Sci Sp Ex. 2008). Runners were randomized to either a control group (continued endurance training) or the weight training group. The latter group added squats to their current endurance training program. The squats were heavy (4 repetition max) and performed for 4 sets of 4 repetitions, three times a week for 8 weeks. The resistance trained runners demonstrated improved strength and rate of force development. In addition, the trained runners showed an improvement in running economy one of the key components of running performance following the program compared to their endurance training only peers. A second study demonstrated a similar improvement in running economy without any change in the athlete’s body weight.
Sedano and colleagues examined the impact of three strength training programs on running economy (J Strength Cond Res. 2013). Runners were randomized to 12 weeks of training in three groups
High Load (3 sets of 7 reps at 70% 1 repetition max)
Low Load (3 sets of 20 reps at 40% of 1 repetition max)
Elastic Bands (3 sets x 25 reps, low load)
As expected, although all 3 groups improved, strength gains and running economy increased the most in the high load group compared to the other two groups. Importantly, no change in body weight was noted in any of the three groups. These studies highlight the importance of strength training in runners but help dispel fears of weight gain or bulk within this group.