A meta-regression analysis for the effect of training duration of change in running economy was carried out. It found that heavy resistance training improves running economy. Over the 16 weeks, percentage change in running economy decreased significantly (-8%) (Denadai, de Aguiar, de Lima, Greco & Caputo, 2017). Furthermore, a study by Häkkinen et al., (2003) examined neuromuscular adaptations during concurrent strength and endurance training versus strength training. It involved sixteen healthy men over 21 weeks. There were 2 strength session per week and 2 strength and endurance sessions per week. Within the strength and endurance condition it found a 18.5% increase in VO2 max (p<0.001). However, it could be suggested that a lower body fat percentage may be associated with the result (20% BF vs 22.5% BF).
There are limitations to concurrent training that need to be accounted for to optimise this training method. For example, in many studies’ resistance training impaired endurance performance as it showed decreases in muscle glycogen, increased muscle soreness, altered gait pattern and finally increased neuromuscular fatigue (Doma, Deakin & Bentley, 2017). To optimise concurrent training there are many things that athletes can do. This includes high intensity training, three hours rest between sessions and resistance training (Baar, 2014). It has been suggested that 2 sessions per week for 24 weeks will improve running economy (Berryman et al., 2017). Also, max force training may also help optimize due to reduced muscle mass (gained from hypertrophy training). Regarding the nutritional supplements, caffeine would be very effective as caffeine improves muscle contraction and it has been well established that 3 mg·kg−1 is effective.
References:
Häkkinen, K., Alen, M., Kraemer, W., Gorostiaga, E., Izquierdo, M., & Rusko, H. et al. (2003). Neuromuscular adaptations during concurrent strength and endurance training versus strength training. European Journal Of Applied Physiology, 89(1), 42-52.
Denadai, B., de Aguiar, R., de Lima, L., Greco, C., & Caputo, F. (2017). Explosive Training and Heavy Weight Training are Effective for Improving Running Economy in Endurance Athletes: A Systematic Review and Meta-Analysis. Sports Medicine, 47(3), 545-554.
Baar, K. (2014). Using Molecular Biology to Maximize Concurrent Training. Sports Medicine, 44(S2), 117-125.
Doma, K., Deakin, G., & Bentley, D. (2017). Implications of Impaired Endurance Performance following Single Bouts of Resistance Training: An Alternate Concurrent Training Perspective. Sports Medicine, 47(11), 2187-2200.
Berryman, N., Mujika, I., Arvisais, D., Roubeix, M., Binet, C., & Bosquet, L. (2017). Strength Training for Middle- and Long-Distance Performance: A Meta-Analysis. International Journal Of Sports Physiology And Performance, 1-27.
The Science behind Running 