Question: How can concurrent training (endurance + strength) be managed to maximize benefits?
Properly designed endurance training (ET) programs are typically low resistance with high repetitions, and aim to increase maximal oxygen uptake, metabolic adaptation, and exercise capacity (1,2). On the contrary, resistance training (RT) programs are high intensity with high resistance and few repetitions, and aim to increase neuromuscular learning, fiber recruitment, strength, and hypertrophy (1,2). Concurrent training (CT) programs are necessary to increase aerobic capacity and strength in certain capacities, but it is important to recognize that CT may produce an interference effect, or conflicting adaptations, resulting in limited maximal gains (1-3). However, it is possible to manage CT along a strength-endurance continuum to maximize benefits according to the needs of the athletes (2).
The benefits of CT vary slightly, based on the goals and primary training focus of the athletes. For example, athletes whose primary focus is ET may include RT in their programs if they desire to increase their strength and body fat loss (1,3). Similarly, athletes whose primary focus is RT may include ET in their programs if they desire to increase their aerobic capacity and metabolic health. However, ET activates AMPK, which negatively regulates protein synthesis, thus inhibiting strength and hypertrophy (2), so it is important to consider the athletes’ goals, as well as other program design variables when considering CT.
When maximum strength and power are not necessary, a strategically designed program may allow for CT that minimizes the interference effect. For example, a meta-analysis by Wilson and colleagues (2012) suggested that CT using high intensity ET on alternating days of RT produced results only slightly below RT alone in hypertrophy, strength, and power. If these are the primary goals, then CT may be beneficial for improving aerobic capacity and reducing body fat, provided the total workload does not yield residual fatigue (2,3).
It is also important to consider the mode of ET, total work volume, duration of recovery between sessions, exercise order when ET and RT are completed in a single session, and length of the training program (1,4). Cycling and sprinting are the two most discussed modes of ET, but again, the needs analysis will aid in selecting the appropriate mode. Cycling yields results more closely related to RT adaptations, whereas sprinting increases eccentric muscle damage (1), but running results in greater loss of body fat (3). The total work volume is generally greater with CT, and residual fatigue and overreaching might affect the subsequent workouts. Research suggests that force production is decreased for six hours following ET, as well as volume lifted during RT following ET (1), which may lead to decreased hypertrophy and strength gains. Because of the implications of residual fatigue, it is recommended to complete the training sessions on alternate days with recovery days built into the program, or complete the RT prior to the ET if completed on the same day (1). Given the increased total volume, it is also important to consider the length of CT programs. Research suggests strength gains can be made through the first 5 – 7 weeks of CT (2,5), followed by a plateau, and then strength can be lost in subsequent weeks (2). CT is beneficial, but must the programs must be properly designed and appropriately implemented.
A final consideration is that much of the research reviews the acute adaptations of CT programs, or the adaptations of short-term CT programs (1-3, 6). So, although CT can be managed to maximize benefits, including adequate recovery time and training blocks of solely ET or RT could be beneficial to maximizing training adaptations.
- Fyfe, J., Bishop, D., Stepto, N. (2014). Interference between resistance and endurance exercise: Molecular bases and the role of individual training variables. Sports Medicine, 44, 743-762.
- Nader, G. (2006). Concurrent strength and endurance training: From molecules to man. Medicine & Science in Sports & Exercise, 38(11), 1965-1970.
- Wilson, J., Marin, P., Rhea, M., Wilson, S., Loenneke, J., & Anderson, J. (2012). Concurrent training: A meta-analysis examining interference of aerobic and resistance exercises. Journal of Strength and Conditioning Research, 26(8), 2293-2307.
- Leveritt, M., Abernethy, P., Barry, B., Logan, P. (1999). Concurrent strength and endurance training: A review. Sports Medicine, 28(6), 413-427.
- Lundberg, T., Fernandez-Gonzalo, R., Gustafsson, T., Tesch, P. (2013). Aerobic exercise does not compromise muscle hypertrophy response to short-term resistance training. Journal of Applied Physiology, 114(1), 81-89.
- McCarthy, J., Pozniak, M., Agre, J. (2002). Neuromuscular adaptations to concurrent strength and endurance training. Medicine and Science in Sports and Exercise, 34(3), 511-519.