Strength Training for Endurance Performance: Part 1
Gym based strength training for endurance athletes is a contentious topic among coaches and athletes. When gym training is mentioned during the weekend bunch ride or lunch time run group talk immediately turns to the fears of bulking up and the potential interference with aerobic endurance. In this article I would like to explore some of the evidence surrounding gym based strength training for endurance athletes and then in Part 2 outline how you can practically apply this into your current training plan to take advantage of the benefits.
Strength training can improve performance in two ways, directly and indirectly. A direct performance improvement is a result of improving the muscles contractile properties and neural activation resulting in a more forceful contraction. Alternatively, indirect training adaptations such as improved posture, core stabilisation and ligament strength make athletes more structurally 'robust'. This increased ‘robustness' of the athlete means that they are able to undergo higher training loads without structurally breaking down or becoming injured. With those two concepts in mind let’s have a look at some of the research in these areas.
Direct performance improvement
When the muscles contract more forcefully the outcome is a potential increase in power production, due to power being a function of force and velocity. Think of force as how hard you push on your bike pedals, drive your legs while running and pull your arm/ paddle when swimming or kayaking. On the other hand velocity is simply how fast you spin your pedals or turn your arms or legs over (it is your cadence, stroke rate or stride rate). The combination of these two is power. By training the muscles to contract more forcefully there is the ability to produce higher force for longer, with the end result of going faster out in the real world.
To improve endurance performance in the gym it appears logical that you would perform high repetition exercises with a low weight, after all that is endurance right? In actual fact it has been found that low repetition, high weight exercises produce the best gains in endurance performance. A study performed in Norway using competitive cyclists found 4 sets of 4 maximal weighted smith-machine squats, 3x per week for 8 weeks resulted in improvements in cycling economy, efficiency and time to exhaustion without any increase in body weight (i.e. they did not ‘bulk up’) or decrease in VO2max (they did not lose aerobic fitness)(Sunde, et al, 2010). This improved performance was due to an increase in neuromuscular function. Meaning that more muscle fibres were activated during the cycling tests allowing more force to be applied to the pedals.
In a critical review on strength training in runners, Yamamovto et al, (2008) concluded that strength training (in particular plyometrics) are beneficial for endurance athletes, with numerous studies showing significant improvements in running performance. Again the majority of these finding were due to neuromuscular factors improving performance, not the actual growth of bigger muscles.
Finally, looking at triathlon performance as a whole. A review paper by Crane (2011) suggests that triathlon performance can be improved through a well planned periodised strength training plan in conjunction with athlete’s current training to improve neuromuscular qualities, economy and musculoskeletal function.
While we have only scratched the surface of the research, it is clear that there are direct performance gains to be had through minimal time investment in the gym for endurance athletes. These improvements are not by building bigger muscles but by improving neuromuscular function to enhance muscle activation and increasing force production.
Indirect performance improvement
Indirect performance improvements through strength training are primarily gained through the development of the athletes’ core stability, leading to improvements in postural control, alignment and an increased injury resilience (Crane, 2011). Numerous studies have been conducted investigating core strength development and performance. Core fatigue has been found to result in altered cycling mechanics that expose the knee to greater stress that can lead to injury (Abt, et al, 2007), while core specific strength training over 6 weeks has been found to improve 5 km running performance (Sato, et al, 2009) and allow athletes to train injury free more often (Hibbs, et al, 2008).
The core is the critical link that connects the two areas of major force generation (the pelvis and shoulder girdle) in the human body. When you look at the human skeleton, the spine is little more than a precariously stacked ‘Jenga tower’ that the shoulder girdle and pelvis are hinged off. The only thing stabilising this stack of vertebrae are the muscles, tendons and ligaments of the core. Like guide wires holding up a ships mast or spokes in a bike wheel if any of these ‘guide wires’ or ‘spokes’ are over-tight or lose then you end up with a mast that is on a lean or a wheel that does not run true.
Due to the nature of triathlon, multisport and other endurance sports athletes end up with tight and over developed muscle groups with others become weak and ‘stretched’ out. This imbalance in the ‘guide wire’ tension causes misalignment of the athletes’ posture which over time can lead to injuries through excessive loading of structures that are not designed to be loaded in such a way or direction.
The example of the athlete in figure 1 above is a classic example of a triathlete or multisporter. Spending large amounts of time riding, running, paddling and swimming cause the muscle groups highlighted in red (pectorals, hip flexors and erector muscle of the spine) to become very strong and tight. These then pull on the shoulders, rounding the spine and tilt the pelvis forwards. The weak/ ‘stretched’ muscles of the upper back, abdominals, glutes and hamstrings are not able to counteract this constant tension and these are often the areas in which injury occurs or ‘tightness’ is felt. I.e. sore shoulders/ back on the bike or ‘tight’ hamstrings when running or paddling. These imbalances are exacerbated during day to day living in the modern world through prolonged sitting, computer work and driving. This further rounds the shoulders, tightening the hip flexors and weakens the abdominals. If an athlete is unable to perform the relatively simple task of maintaining correct posture, then they are going to struggle in the long term to perform optimally in the complex tasks of running, swimming, kayaking and cycling not to mention their ability to live a long pain free life outside of their sport.
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While strength training can appear at first glance to be non-specific (and even opposing) to the demands of triathlon and multisport, appropriately designed strength training programmes can improve competitive performance both directly and indirectly.
In the next ‘Science of Endurance’ article I will outline how to integrate gym based strength training into your training programme and where you should be putting your focus to get the best direct and indirect performance benefits.
If you have any questions about strength training for endurance athletes please contact me.
Sport Scientist and Performance Coach
Exponential Performance Coaching
Abt, Smoliga, Brick, Jolly, Lephart, and Fu. Relationship between cycling mechanics and core stability. J. Strength Cond. Res; 21(4):1300–1304.2007.
Crane. Strength training for endurance performance: A triathlon perspective. J Aust. Strength Cond. 19(3)65-76. 2011
Hibbs, Thompson, French, Wrigley and Spears. Optimizing Performance by Improving Core Stability and Core Strength. Sports Med; 38 (12): 995-1008, 2008
Sunde, Støren, Bjerkaas, Larsen, Hoff, and Helgerud. Maximal strength training improves cycling economy in competitive cyclists. J Strength Cond Res; 24(8):2157–2165, 2010
Sato and Mokha. Does core strength training influence running kinetics, lower-extremity stability, and 5000-m performance in runners? J Strength Cond Res; 23(1): 133–140,2009
Yamamoto, Lopez, Klau, Casa, Kraemer, and Maresh. The effects of resistance training on endurance distance running performance among highly trained runners: a systematic review. J Strength Cond Res; 22(6): 2036–2044, 2008