New Research Says Training Your Muscles at a Full Stretch Could Enhance Gains

A training technique that involves completing long-length partial reps has garnered interest in the fitness space over the past year. Several studies have pointed to the muscle-building benefits of focusing on the lengthened phase of lifts.

This technique involves performing multiple 'half reps' in the portion of the lift where the muscles are most lengthened or stretched. For example, the stretched portion of lat pull-downs or chest fly, or the bottom portion of pull-ups or calf raises.

Now, a yet to be published review weighs up the current evidence, and whether this is a training technique we should be implementing in our workouts to make the most out of our reps, and further increase muscle mass.

The Study

The study led by exercise researchers aimed to systematically review the current evidence to evaluate if resistance training at longer muscle lengths results in greater hypertrophy compared to shorter muscle lengths. It's important to note that the review hasn't been published quite yet, and therefore hasn't been cited.

The Methods

The systematic review included eight studies with a total sample size of 120 participants. The studies met the following inclusion criteria:

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• Must be a resistance training intervention study comparing training at longer muscle lengths to shorter muscle lengths.
• Must assess both muscle length and muscle size before and after the intervention.
• Includes healthy adults over 18 years old.
• Minimum training intervention duration of four weeks.

The Results

The review found that both muscle size and length showed greater increases following longer muscle length training compared to shorter muscle length training. However, evidence across studies was mixed. The underlying causes for hypertrophy from longer muscle length resistance training remains undetermined at this point.

The researchers also found that resistance training causes hypertrophy through mechanical overload, by increasing protein synthesis via mTORC1 signalling (a sensor that controls protein synthesis) and other pathways. It was also noted that training in full range of motion (ROM) during reps may still appear to be superior for gaining muscle mass, but the extent of this may depend on the muscle length at which the resistance training is performed.

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The Conclusion

The study concludes that understanding the effectiveness of training at longer muscle lengths could influence resistance training protocols for improved muscle growth. It also added that training at longer muscle lengths may be particularly beneficial for athletes and anyone focused on strength training.

According to researcher Menno Henselman, 'The benefits of emphasising long muscle lengths in your training appear to be robust. They're the likely reason why training with a full range of motion (ROM) generally beats training with a shorter ROM. Emerging research suggests going all-in on lengthened partials may be even better than full ROM training, but that remains to be confirmed.'