Wednesday, September 21, 2011


Today, I would like to share with you my thoughts on the benefits and disadvantages of combining strength and endurance at the same training session. My thoughts are based on two recent studies published in well respected, high quality scientific journals last month. 

As you all know, combining endurance and strength training (concurrent training) may change the adaptations compared with single mode training. The mechanism behind this hypothesis is still unclear. 

In the first of these studies, 10 healthy subjects performed either only endurance exercise (E: 1h cycling at ~65% of VO2max) or endurance exercise followed by resistance exercise (ER: 1h cycling + 6 sets of leg press at 70-80% of 1 repetition maximum) in a randomized cross-over design (Wang et al., 2011). Muscle biopsies were obtained before and after exercise. The results showed that resistance exercise, performed after endurance exercise, amplifies the adaptive signaling response of mitochondrial biogenesis compared with single-mode endurance exercise. The mechanism may relate to a crosstalk between signaling pathways mediated by mTOR. Simply, resistance training performed after endurance exercise may amplify aerobic adaptations. Thus, we can speculate, although not directly examined in this study, that this type of training will improve aerobic performance more than endurance training alone.

In the second study, Ronnestad et al (2011) compared the effect of 12 weeks of strength training combined with a large volume of endurance training (S+E) with the effect of strength training alone (S) on the strength training adaptations. Well-trained cyclists with no strength training experience performed heavy strength training twice a week in addition to a high volume of endurance training during a 12-week period. A group of non-strength trained individuals performed the same strength training as S + E, but without added endurance training. Thigh muscle cross-sectional area, 1 repetition maximum (1RM) in leg exercises, squat jump performance, and peak rate of force development (RFD) were measured. Following the intervention period, both S + E and S increased 1RM strength, thigh muscle cross-sectional area, and squat jump performance (p < 0.05), and the relative improvements in S were greater than in S + E (p < 0.05). S increased peak RFD while S + E did not, and this improvement was greater than in S + E (p < 0.05). These results suggest that the strength training response on muscle hypertrophy, 1RMstrength, squat jump performance, and peak RFD is attenuated in well-trained endurance athletes during a period of concurrent endurance training.

Taking this evidence together it seems that:

  • Resistance training performed after endurance exercise may amplify aerobic adaptations 
  • Endurance exercise performed with resistance exercise at the same session may result in lower level of hypertrophy and lower improvement in power than performing resistance training only. 

For more reading
Ronnestad et al. High volume of endurance training impairs adaptations to 12 weeks of strength training in well-trained endurance athletes. Eur J Appl Physiol, 2011 [Epub ahead of print]
Wang et al. Resistance exercise enhances the molecular signaling of mitochondrial biogenesis induced by endurance exercise in human skeletal muscle. J Appl Physiol, 2011 [Epub ahead of print]

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