The concept of elite marathon runners, triathletes, or cyclists dedicating time to lifting heavy weights seems immediately counter-intuitive. We typically associate these lean and efficient athletes with high volume, low intensity training. Indeed, the whole idea of endurance athletes spending time in the weights room is deeply stigmatised, and most will reject outright that they should engage in any form of (legitimate) strength training.
Perhaps the most commonly cited reason for endurance athletes avoiding strength training is the fear of ‘gaining muscle mass’ (and metamorphosing into the stereotypical gym rat?) This fear of gaining mass, however, is completely unfounded16. A fair comparison would be a bodybuilder avoiding running for fear of breaking 17 minutes in a 5 km. Gaining muscle is, for some, a training goal in itself and requires specific training and lifestyle dedication. Muscle hypertrophy is massively endergonic (that is, it requires large amounts of surplus energy), which is somewhat incompatible with the high volume training schedules of most competitive long-distance athletes. Furthermore, the biochemical pathways that regulate endurance adaptations and muscle hypertrophy may be, to some extent, antagonistic8,17.
Many endurance athletes will also avoid heavy resistance training due to a basic intuition—how could lifting heavy weights possibly benefit an Ironman triathlete? This seems a fair assumption given an elementary understanding of training specificity. However, a deeper understanding of our physiology, and a look at the emerging literature, warrants something of a paradigm shift in our approach to endurance training.
What Does the Research Say?
The compatibility of strength and endurance training has been investigated for nearly three decades4. Concurrent training has been found to negatively affect strength-training adaptations, and a recent review of the literature12 concludes:
- Athletes training for maximal power should avoid any form of endurance training
- By comparison, maximal strength/hypertrophy training is not as adversely affected by concurrent training, but it is advisable that these athletes use high-intensity aerobic modalities for their endurance training
(The molecular mechanisms that underpin the interference of concurrent training with power & strength adaptations are explored thoroughly in Ref. 8)
However, the effects of concurrent training on endurance adaptations appear to be more compatible, producing complementary, rather than contradictory, effects4.
NB: Maximal-Strength Training (MST) == High loads (>80% 1RM), few reps (~3–6), long rest intervals between sets (3–4 min)13.
Millet et al., 20027
- National and international level triathletes, undergoing winter base training.
- Exercise(s): hamstring curls, leg presses, parallel squats, leg extensions, calf raises.
- 14 week intervention period.
- Protocol: 3–5 sets of 3–5 reps to failure at >90% 1RM, 2x a week + normal training.
- Significantly greater improvement in running economy and speed at VO2max in the resistance-training group.
- No body weight change.
Storen et al., 20089
- Well trained distance runners.
- Exercise(s): half squats.
- 8 week intervention period.
- Protocol: 4 sets of 4 repetitions to failure, 3x a week + normal run training.
- Resistance training group significantly improved their running economy and time to exhaustion at VO2max, while the control group (normal training) showed no significant change in any of the measured parameters.
- No body weight change.
Sunde et al., 201010
- Competitive road cyclists, studied in the off-season.
- Exercise(s): half squats (in a smith machine, much to the disgust of any strength and conditioning professional I’m sure!)
- 8 week intervention period.
- Protocol: 4 sets of 4 repetitions to failure, 3x a week + normal bike training.
- Resistance training group significantly improved their cycling economy and time to exhaustion at VO2max.
- No body weight change.
In addition, the inclusion of plyometric training (vertical jumps, hopping etc.) within a running programme also has the potential to improve movement economy11.
How Does it Improve Endurance Performance?
As with most things, it’s hard to give a certain answer to this question, but it could be explained through several (likely interacting) mechanisms:
- With each movement cycle (running stride/pedal stroke) athletes must produce a certain amount of force. This force, combined with turnover (cadence), dictates pace/speed. The recruitment of muscle fibres, notably slow-twitch and fast-twitch, is related to the force of contraction relative to maximum force, in that higher %max forces require more fast-twitch fibres. By increasing maximum force (as with MST), force per movement cycle (as a percentage of max) is effectively reduced. This, in turn, will lead to a greater relative recruitment of slow-twitch fibres, which are inherently more efficient and fatigue resistant14,15.
- Improved movement economy7,9,10 (i.e. faster pace/speed for a given oxygen consumption)—though this is less likely in elite athletes, particularly elite cyclists19.
- Resistance training may cause a migration of fast-twitch fibres towards their more ‘aerobic’ subtype16.
- Strength training also reduces time to peak force16, which will increase relaxation time within each movement cycle, permitting greater blood flow.9
- Improved neural activation, efficiency, and synchronisation.7 In short, like giving your muscles a “software upgrade”.
(Reference 18 reviews these mechanisms in more detail)
Practical Training Considerations
Heavy resistance training can impair muscle force generation capacity for 24–48 hrs1, which could impair endurance performance for the same time period. However, muscle function has been shown to recover faster following a run session5, which likely applies to other modalities (biking, swimming…)—though this will obviously depend on the nature of the session. As such, resistance training performed prior to endurance training will (probably) have a greater additive fatigue effect than if endurance training were performed prior to resistance training. It seems logical, therefore, that endurance athletes schedule their resistance training as the last session of the day in order to minimise cumulative fatigue and maximise recovery time prior to subsequent endurance training.
NB: performance enhancement from resistance training is by no means immediate. It has been suggested that 12 weeks is the minimum period required to elicit performance effects16.
- Weight training should follow MST protocols (high weight, low reps, long rests), and benefits may be augmented by the inclusion of plyometric training within those sessions16.
- Resistance training should be undertaken as the final session of the day, thus allowing for greater recovery. If this isn’t possible, it is advisable to allow a minimum of 6 hours between strength training and endurance training sessions performed on the same day2,6.
- 2–3 sessions a week is likely adequate to realise performance benefits.
- High intensity endurance sessions should be avoided in the day following resistance training, which should ensure greater quality in those sessions5.
- Focus on the muscles specific to your sport (i.e. a cyclist should focus on lower body movements)—but general, whole-body conditioning should not be neglected.
- While most studies use some form of machine weights, this is largely for control purposes. Ideally athletes should focus on the “main” free weight lifts: squats, deadlifts, bench presses, pull-ups, & overhead presses.
- Try to perform the concentric phase (i.e. the ‘active’ phase) as fast as possible. While the movement velocity may not necessarily be high, it is the intention that appears to be important18.
- Keep the eccentric phase (i.e. the ‘down’ phase) slow, as fast eccentric contractions are associated with greater muscle damage3,6.
- Technique is crucial. If you’re unfamiliar with the above-mentioned movements either do your homework or contact a credible trainer.
- Leave your ego at home. If you have little prior experience with strength training you can’t expect to lift heavy weights straight away. The gym isn’t a competition (unless it’s a CrossFit gym…)
- While you should ultimately be looking to follow MST protocols, I would strongly advise against going straight in at ~5 RM loads. For the first weeks, assuming you haven’t engaged in any form of resistance training previously, use lighter loads and higher reps (~10) and focus on form. As you get more familiar with the lifts, you can start increasing the weight.
- If you can’t lift something with proper form, don’t lift it.
- Remember your priorities. You’re not a power lifter, sport-specific training comes first.
- Hakkinen, K., Pakarinen, A., Alen, M., Kauhanen, H., and Komi, P.V. Daily hormonal and neuromuscular responses to intensive strength training in 1 week. Int. J. Sports Med. 9(6): 422–428, 1988.
- Deakin, G.B. Concurrent training in endurance athletes: the acute effects of strength training on the recovery of muscle force generation capacity and cycling efficiency, post-training. PhD thesis, Southern Cross University, Australia. 2004.
- Fride N, J., Sjostrom, M., & Ekblom, M. Myofibrillar damage following intense eccentric exercise in man. International Journal of Sports Medicine 4: 170–176, 1983.
- Davis, W.J., Wood, D.T., andrews, R.G., Elkind, L.M. and Davis, W.B. Concurrent training enhances athletes’ strength, muscle endurance, and other measures. Journal of Strength and Conditioning Research 22(5): 1487–1502, 2008.
- Doma, K. and Deakin, G.B. The effects of strength training and endurance training order on running economy and performance. Applied Physiology, Nutrition, and Metabolism 38(6), 651–656, 2013.
- Doma, K. and Deakin, G.B. The acute effects intensity and volume of strength training on running performance. European Journal of Sport Science 14(2): 107–115, 2012.
- Millet, G.P., Jaouen, B., Borrani, F. and Candau, R. Effects of concurrent endurance and strength training on running economy and VO2 kinetics. Med Sci Sports Exerc. 34(8): 1351–1359, , 2002.
- Nader, G.A. Concurrent strength and endurance training: from molecules to man. Med Sci Sports Exerc. 38(11): 1965–70, 2006.
- Storen, O., Helgerud, J., Stoa, E.M. and Hoff, J. Maximal strength training improves running economy in distance runners. Med Sci Sports Exerc. 40(6): 1087–1092, 2008.
- Sunde, A., Storen, O., Bjerkaas, M., Larsen, M.H., Hoff, J. and Helgerud, J. Maximal strength training improves cycling economy in competitive cyclists. Journal of Strength and Conditioning Research 24(8): 2157–2165, 2010.
- Turner, A.M., Owings, M. and Schwane, J.A. Improvement in running economy after 6 weeks of plyometric training. Journal of Strength and Conditioning Research 17(1): 60–67, 2003.
- Wilson, J.M., Marin, P.J., Rhea, M.R., Wilson, S.M., Loenneke, J.P. and anderson, J.C. Concurrent training: a meta-analysis examining interference of aerobic and resistance exercises. Journal of Strength and Conditioning Research 26(8): 2293–2307, 2012.
- Hoff J., Tjonna A.E., Steinshamn S., Hoydal M., Richardson R.S., and Helgerud J. Maximal strength training of the legs in COPD: a therapy for mechanical inefficiency. Med Sci Sports Exerc. 39(2): 220–226, 2007.
- Hickson, R. C., B. A. Dvorak, E. M. Gorostiaga, T. T. Kurowsln, and C. Foster. Potential for strength and endurance training to amplify endurance performance. J. Appl. Physiol. 65: 2285–2290, 1988.
- Hoff J., Helgerud J., and Wisloff U. Endurance training into the next millennium; muscular strength training effects on aerobic endurance performance: a review. Am J Med Sports. 4: 58–67, 2002.
- Aagaard, P. and Andersen, J.L. Effects of strength training on endurance capacity in top-level endurance athletes. Scandinavian Journal of Medicine & Science in Sports 20(S2): 39–47, 2010.
- Baar, K. Training for endurance and strength: lessons from cell signaling. Med Sci Sports Exerc. 38(11): 1939–1944, 2006.
- Ronnestad, B.R. and Mujika, I. Optimizing strength training for running and cycling endurance performance: A review. Scandinavian Journal of Medicine & Science in Sports doi: 10.1111/sms.12104.
- Sassi, A., Impellizzeri, F.M., Morelli, A., Menaspa, P. and Rampinini, E. Seasonal changes in aerobic fitness indices in elite cyclists. Applied Physiology, Nutrition, and Metabolism 33(4): 735–742, 2008.