Exercises such as calf raises, leg curls and ab crunches are frequently used by personal trainers and strength & conditioning coaches with a background in bodybuilding or physiotherapy. In these exercises, it is attempted to train certain muscles such as the gastrocnemius or the hamstrings in isolation. It is believed that this isolated single-joint training eventually leads to an improved sport performance.

However, muscles such as the gastrocnemius and the hamstrings function in a complex inter-muscular coordination pattern in many sport movements. Specifically, these muscles span two joints (i.e., they are bi-articular) and have a crucial role in energy transportation from one joint to the other joint (4, 5). Single-joint training of these muscles therefore contrasts the functioning of these muscles in many sport movements.

Several sport coaches have long believed that this isolated single-joint training does not contribute to performance. Evidence from computational modelling studies and recent experimental studies among humans suggests that these coaches may have been right. In fact, the evidence suggests that isolated single-joint training may even be detrimental to performance!

“Evidence suggests that single-joint training may be detrimental to performance!”

Single-joint training and performance

In a classic modelling study by Bobbert and Van Soest (1) it was shown that an increase in muscle strength without an improved coordination lead to a decrease in vertical jump performance. Specifically, they increased the strength of the leg extensors by 20%, but they did not adjust the onset of muscle activation and showed that jump performance decreased by almost 10 cm.

Recently, these results have been replicated in human participants. Dalen, Welde, van den Tillaar and Aune (2) divided sport science students in a single-joint and multi-joint group. The single-joint group performed a ballistic squat without plantar flexion and a plantar flexion movement separately, while the multi-joint group performed a ballistic squat in which the plantar flexion movement was incorporated (figure 1).

Figure 1. A multi-joint group. B single-joint group. The single-joint group performed the squat on a box to preclude plantar flexion. Adapted from Dalen et al. (2).

The idea was that both groups trained the strength of the gastrocnemius, but the energy transporting role of the gastrocnemius (i.e., the coordination) was not trained in the single-joint group, while it was trained in the multi-joint group.

They showed that both groups improved their 1-RM squat, but only the multi-joint group improved the vertical jump performance. Moreover, the single-joint group actually showed a small decrease in jump performance, probably as a result of detrimental changes in the coordination (3).

These findings highlight the importance of coordination as an increase in strength by single-joint training of bi-articular muscles did not contribute to an improved performance and was even detrimental to performance!

Conclusion and practical applications

–         Single-joint training of bi-articular muscles contrasts the functioning of these muscles during sports movements and may actually be detrimental to performance;

–         Exercises such as hamstrings curls, knee extensions, calf raises, triceps extension, biceps curls and ab crunches probably all isolate the functioning of the bi-articular muscles and may therefore be detrimental to performance;

–         Trainers should carefully think about the functioning of muscles during sports and incorporate exercises in which these muscles are trained in appropriate coordination patterns.

 

References:

1.           Bobbert MF and Van Soest AJ. Effects of muscle strengthening on vertical jump height: A simulation study. Med Sci Sports Exerc 26: 1012-1020, 1994.

2.           Dalen T, Welde B, van den Tillaar R, and Aune TK. Effect of single vs. multi joint ballistic resistance training upon vertical jump performance. Acta Kinesiologiae Universitatis Tartuensis 19: 86-97, 2013.

3.           Leirdal S, Roeleveld K, and Ettema G. Coordination specificity in strength and power training. Int J Sports Med 29: 225-231, 2008.

4.           van Ingen Schenau GJ. From rotation to translation: Constraints on multi-joint movements and the unique action of bi-articular muscles. Hum Mov Sci 8: 301-337, 1989.

5.           van Ingen Schenau GJ, Pratt CA, and Macpherson JM. Differential use and control of mono-and biarticular muscles. Hum Mov Sci 13: 495-517, 1994.

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Is single-joint training detrimental to sport performance?

4 thoughts on “Is single-joint training detrimental to sport performance?

  • 14/07/2017 at 12:04 am
    Permalink

    Improvement in sports performance is the ultimate goal for a bona fide athlete who has been in training 1-2 or more years. Isn’t the main objective when athlete first stars, as for example, at 13-14 (or younger) to first develop the athlete and to prepare him for the training that follows? It is certainly not to improve his performance, especially when looked at from a multi-yearr periodization scheme. This is where the use of single joint exercises is especially important.
    I also doubt that the studies that you quote used novice athletes. If they did, there is something definitely wrong with the studies.

    In regard to using single joint exercises for skill improvement or correction I doubt very much that the study you quote develops or reinforces the neuromuscular pathway in exactly the manner seen in execution of the sports skill, in the single joint exercise.

    Thus to answer the question of whether single joint exercises are of any benefit we must first examine the athletic population, and years of training,And objectives of the training

    Reply
    • 14/07/2017 at 10:31 am
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      Thanks again for your comments. It is good to hear your thoughts on this topic.

      I agree that preparation for more training and competition later in life is an important aspect in youth athletes. However, I still don’t think that single-joint exercises are necessary for this preparation. How does the improved strength of such training eventually transfer to the performance later in life? Does it even have a (positive) transfer? Why can’t we do this preparation using multi-joint exercises?

      I had a quick look at the studies in the review and there were several studies that used untrained participants.

      The constraints-led approach is actual an approach in which the skill is practiced in a sport specific setting, by changing the constraints of the task, environment and athlete. The neuromuscular pathways are therefore trained in a very specific way for the skill. In contrast, and just as an additional example, 6 weeks of isokinetic strength training for the knee extensors did not improve kicking velocity in soccer players with no experience with resistance training (1).

      I agree that more (long-term) research is required in different populations but it will take time before such studies are executed.

      (1) Aagaard, P., Simonsen, E. B., Trolle, M., Bangsbo, J., & Klausen, K. (1996). Specificity of training velocity and training load on gains in isokinetic knee joint strength. Acta Physiologica, 156(2), 123-129.

      Reply
  • 13/07/2017 at 5:59 pm
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    It may sound plausible but it is not practical. Has periodization been taken into consideration?

    Single joint exercises are critical for establishing a base ( foundation) to do multi-joint exercises. It is not an either or proposition. Single joint exercises are the only exercises that can be used for strengthening individual joints and joint actions. They also critical for making corrections in skill execution

    Reply
    • 13/07/2017 at 6:50 pm
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      Hi Michael,

      Thanks for your comment. I did not specifically consider periodization for this post, but it is an interesting topic. I wonder why you thinkthat single-joint exercises are critical for establishing a base for multi-joint exercises? Would this not be a very indirect approach to improve sports performance? In the end, multi-joint exercises only have an indirect contribution to sports performance so performing single-joint exercises to improve multi-joint exercises to improve sports performance is a very indirect approach.

      Furthermore, a recent review found no additional benefit of performing single-joint exercises on muscle strength to multi-joint exercises (1), so I’m not sure that the single-joint exercises have a lot of benefits. Making corrections in skill execution can also be done using other approaches (e.g., constraints-led approach), so again I don’t think we necessarily need single-joint exercises for this.

      Just to be clear: I’m not saying we should absolutely never perform a single-joint exercise, but I do think that we should think more critical about their use. In my experience a lot of coaches simply use them because they have been used by body-builders in the past and they have had a great influence on program design for strength and conditioning.

      Reference
      (1) Gentil, P., Fisher, J., & Steele, J. (2017). A review of the acute effects and long-term adaptations of single-and multi-joint exercises during resistance training. Sports medicine, 47(5), 843-855.

      Reply

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