22 June 2012
I am sure many of us have had to stop running for a period of time. In desperation to maintain our fitness we find ourselves delving into the garage to pull out that old rusty bike.
Perhaps the novelty of running training everyday has begun to waiver and in a moment of weakness you are walking away from the bike shop with a shiny new machine? Or are you like myself who sometimes migrates into the gym when the temperatures plunge and the thought of another day with cold, wooden fingers is just too unappealing?
The purpose of this article was to broach the difficult topic of cross-training for athletic performance and to review the literature to determine if cycle training impedes or supports our running.
Despite strong attempts to uncover the most recent research on the crossover between cycling and running, very little appears to have been conducted in this area. The most significant information discusses the need to balance swimming, cycling and running for optimal triathlon performance. For example, Millet et. al. (2002) tried to determine the extent of specificity between disciplinary training in triathletes. They concluded that swimming appears to be a highly specific activity, which does not gain nor provide benefits from, or to, the other disciplines. This is also supported by Tanaka (1994) who suggested that swimming training may result in minimum transfer of training effects, especially on the cardiovascular system. However, Millet et. al. did determine that cross-training effects do occur between cycle training and running performance in the elite triathletes.
In a later study, Millet et. al. (2009) conducted a synopsis of the literature to determine what the physiological differences are between cycling and running.
They compared physiological variables such as maximal oxygen consumption (VO2max) and heart rate variances in triathletes, cyclists and runners. At the conclusion of their comparisons they determined that runners and cyclists can achieve similar VO2max results in their specialized disciples but not if they attempt to conduct the test in their non-targeted sport. A triathlete who specializes in both disciplines may achieve equal results on a treadmill and a cycle ergometer.
Within the literature they also found an increased rate and level of fatigue in runners than in cyclists that caused a decrease in maximal strength. Perhaps due to this, there were significant differences in heart rate training zones for runners and cyclists. Therefore, they concluded that running places the body under greater demands and that there is more physiological training transfer from running to cycling than visa versa. Tanaka et. al. (1994) supports this be stating, ‘the nonspecific training effects seem to be more noticeable when running is performed as a cross-training mode’.
Foster et. al. (1995) suggested that cycle cross-training can create positive muscular changes to aid running performance but not to the same degree as increasing one’s specific training. More recently, Smith (2012) conducted a study of cross-training benefits on the cardiovascular system of thirteen athletics athletes over six weeks. He concluded that his subjects displayed no significant differences in their running economy or VO2max results post cycle training. ‘Cross-training effects never exceed those induced by the sport-specific training mode… the principles of specificity of training tend to have greatest significance in the highly trained athlete.’ (Foster et. al., 1995)
White et. al. (2003) conducted a study to examine whether substituting 50% of run training volume with cycle cross-training would maintain the competitiveness of female distance runners over a five week recuperation phases. They noted that although there was a slight decrease in their 3000m times, there was no actual loss of aerobic performance.
Therefore, for the elite runners, this discussion of the most relevant literature suggests that nothing beats the specificity of running to run. During the height of the season and in the lead up to major races, it would be preferable that cycle cross-training is not used as a substitute to running training. The most positive effects of cycle training could be during the off-peak time or following injury. During these periods, cycle training may maintain previous aerobic performance up to around six weeks. Following this, a decrease in running function may occur.
So far we have focussed on the training effects in the elite athlete but what significance does this hold for us mere mortals? After all, cross-training is a widely used approach for structuring a training programme. For the general population, evidence suggests that cross-training may be highly beneficial in improving overall fitness. Similarly, cross-training may be an appropriate supplement when beginning running and during periods of overtraining or psychological fatigue, such as during periods of high intensity employment (Tanaka, 1994). Finding the right balance of cross-training to running is a matter of working through your goals and determining the importance of running outcomes. A good coach should be able to assist you with this.
Finally, if cycling is your main sport, the nature of the increased physical demands of running may actually lead to a positive effect on cycle performance.
Foster, C., Hector, L.L., Welsh, R., Schrager, M., Green, M.A., & Snyder, A.C. (1995). Effect of specific versus cross-training on running performance. European Journal of Applied Physiology and Occupational Physiology. 70(4), 367-372, DOI: 10.1007/BF00865035
Millet, G.P., Candau, R.B., Barbier, B., Busson, T., Rouillon, J.D., & Chatard, J.C. (2002). Modelling the transfers of training effects on performance in elite triathletes. International Journal of Sports Medicine. 23(1), 55-63. DOI: 10.1055/2-2002-19276
Millet, G.P., Vleck, V.E. & Bentley, D.J. 2009. Physiological differences between cycling and running: Lessons from triathletes. Sports Medicine; 39(3), 179-206
Smith, A. 2012. Effect of independent crank cycling training on running economy in collegiate distance runners (unpublished work).
Tanaka, H. (1994). Effects of cross-training. Transfer of training effects on VO2max between cycling, running and swimming. Sports Medicine 18(5), 330-339.
White, L.J., Dressendorfer, R.H., Muller, S.M., & Ferguson, M.A. 2003. Effectiveness of cycle cross-training between competitive seasons in female distance runners. The Journal of Strength and Conditioning Research. 17(2)