New Study Finds Eccentric-Only Lifting Can Reduce Muscle Stiffness
It’s a commonly held belief that lifting heavier weights leads to muscle stiffness, making everyday tasks difficult. However, new research challenges this notion. By focusing on specific phases of lifting, such as the eccentric (lowering) phase, and using a large range of motion, you can actually reduce muscle stiffness while simultaneously increasing strength and size. This approach highlights the importance of controlled and varied movements in resistance training for optimal muscle health and development
Lead researcher Raki Kawama from Doshisha University's Faculty of Health and Sports Science states, 'During my time as a coach, I often encountered the myth that excessive resistance training increases passive muscle stiffness. Inspired by previous stretching studies, I hypothesised that passive muscle stiffness could be decreased by resistance training using a combination of eccentric contractions, long muscle lengths, and a long contraction duration.'
The Study
The study, which published in Medicine & Science in Sports & Exercise, aimed to find out the effects of different training frequencies when performing the stiff leg deadlift at half to full range of motion, eccentric only, over 10 weeks.
36 young men were assigned to two training groups:
W2 group: trained twice a week
W3 group: trained three times a week (higher frequency and volume)
There was also a control group who didn't have an exercise protocol.
After an initial screening and a practice set, participants performed three sets of 10 reps of eccentric-only stiff leg deadlifts with extended muscle lengths. Over the 10 weeks, the weights progressively increased to 60%, 65%, and 70% of body mass. Each set was followed by a 2-minute rest period
Before and after the study, the researchers measured the stiffness of the hamstring muscles (flexibility), the maximum force the hamstrings could generate while attempting to bend the knees against an immovable object (strength), and the area of the individual hamstring muscles (the size).
The Results
Researchers found that:
In the W3 group, the stiffness of inner part of the hamstring (the semimembranosus) significantly decreased, while the other hamstring muscles did not show any change
There were no significant changes in the stiffness of the hamstrings in the W2 or control groups
The strength and size of the inner part of the hamstring was significantly increased in both training groups
The results indicate that long-term eccentric-only resistance training at extended muscle lengths, with a high weekly frequency and total training volume, can effectively decrease muscle stiffness.
The Conclusion
Prof. Kawama concluded, 'Our findings challenge the traditional belief that passive muscle stiffness could only be decreased through stretching. This study has revealed a training modality to chronically decrease the passive stiffness of a specific muscle while simultaneously increasing muscle strength and size. This represents the first step towards a paradigm shift from static stretching to resistance training for chronically decreasing passive muscle stiffness.'
He continued, 'In the next five to ten years, this new method could significantly improve the effectiveness of training and rehabilitation programs, leading to better outcomes for athletes and patients.'
What Does This Mean for Us?
It's usually thought that sitting in stretches for long periods of time is the only way to decrease muscle stiffness and improve flexibility. This study shows that there are benefits of lifting weights beyond strength and size, and we could see improvements in flexibility when training at long muscle lengths, using full range of motion. It also challenges the idea that lifting weights will make your muscles stiff, whereas training more often could actually decrease muscle stiffness.
It's important to note that the researchers do mention limitations to the study, one of which is that the total training volume differed among the groups. However, they also noted that a recent systematic review showed no significant correlation between total weekly stretching duration and long-term muscle stiffness reduction. Therefore, the differences between groups might be due to the frequency of the stretching sessions rather than the total volume.
Training at longer muscle lengths has recently been studied extensively showing its benefits for gaining muscle size. This new research further emphasises the importance of maximising the range of motion during of our reps.
While training eccentric-only moves can be challenging without a spotter or dropping weights (except for exercises like pull-ups and push-ups), research suggests focusing on eccentric training can boost muscle flexibility, strength, and size. To incorporate this into your routine, try to emphasise the following:
Using full range of motion during your reps
Spending time in the long lengthened portion of the reps
Training more frequently over the week
Including eccentric only moves if possible
Moving in varied movement patterns in your training sessions
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