S ho rt vs. lo ng m uscle le ngth training fo r m axim iz ing hy pe rtro phy ?

Long muscle length training is the in vogue trend within the fitness community. Previous research has demonstrated there is a regional hypertrophy and 1RM strength effect with partial range of motion training at short (i.e. flexed knee creating a shorter hamstring) and long muscle lengths (i.e. extended knee and flexed hip creating a long hamstring) (see ). Another study HERE found long muscle length training superior to short muscle length in biceps thickness (see ). However, HERE this was a short 5 week study so extrapolating these results to longer time frames is challenging. Further, 1RM strength has not been studied in long vs. short muscle length interventions within the upper body Therefore, this study aimed to compare 1RM strength and regional muscle hypertrophy of the biceps following periods of short and long muscle length training.

19 untrained women (age = 22.8 ± 10.5 yr) performed a unilateral seated dumbbell preacher curl in a withinsubject experimental design 3 times per week for 8 weeks. Each arm was randomized into an initial range of motion (iROM) or final range of motion (fROM) training intervention. The iROM condition performed preacher curls from 0° (fully extended) to 68° (halfway) of elbow flexion. fROM condition started at 68° and finished at 135° (perpendicular to the floor). The arm that started each session was alternated and all 4 sets per arm in each session were taken to volitional failure.

Before and after the 8 week intervention, biceps cross sectional area (CSA) was assessed with ultrasound at 50% and 70% of the distance from the acromion to the lateral epicondyle of the upper arm (shoulder to elbow, halfway down to approximately ¾ down to the elbow). CSA at 50% and 70% were summed to estimate overall biceps hypertrophy. 1RM strength was also assessed on the dumbbell preacher curl through a full range of motion.

The iROM condition led to a significantly greater CSA than fROM at 70% of biceps length but not at 50%. CSA summed increase was not significantly different between conditions. iROM showed significantly greater 1RM strength increase than fROM.

These findings add further evidence to the growing pile on the superior stimulus achieved via long muscle length training. For example, Dustin Oranchuk reached similar conclusions in his popular isometric training review (see ). But what does this mean for different HERE training populations?

§ Use a full range of motion to maximize strength and hypertrophy within general and athletic populations.

§ Use end range partial reps as an intensity technique during overreaching or high-volume training cycles for hypertrophy. For example, performing a set of 10 biceps curls close to failure and finishing with 6-10 end range partial reps from bottom to ¼ or ½ way Legendary bodybuilding coach and influencer John Meadows has been doing these for years, which you can see on his YouTube channel I’ll post in the links below

This paper also adds to the body of research surrounding regional muscle hypertrophy. For example, end range leg extensions preferentially target the distal quadriceps (see HERE).

And we can preferentially target the upper and lower abs with crunches and leg raises respectively (see ). This could be useful for targeting the lower quads during return to HERE play training from knee injury

One strategy that can be employed by athletes who don’t want to increase muscle mass due to performance or weight class restrictions and who are close to peaking is to reduce the range of motion training at short muscle lengths. For example, quarter squats and deadlifts from blocks. These exercises can limit muscle growth while potentially leading to better speed and power improvements (see HERE).

“If your goals are to maximize hypertrophy, you’re short changing yourself if you’re not training with a full range of motion. The mechanisms leading to the increased hypertrophic response are unknown but we could speculate a multitude of factors like increased work, increased eccentric contraction, and greater time under tension. Regardless, save the short muscle length partial exercises for athletic performance peaking. It should also be noted this study only compared two partial range of motion conditions. Would the iROM condition outperform a full ROM condition?”