Examining the effectiveness of partial vs. full range of motion during resistance training Original paper

In this meta-analysis of randomized controlled trials, partial and full range of motion resistance training were similarly effective for improving muscle size, sports performance, and strength. However, depending on the specific context, one method can prove more useful than the other.

The effects of partial vs. full range of motion (ROM) resistance training on body fat, sports performance, and resistance training outcomes, including muscle size, strength, and power.

A total of 658 participants.

The average ages and percentages of men and women in the meta-analysis were not reported.

The researchers conducted a systematic review and meta-analysis of 23 randomized controlled trials (RCTs) to examine the effects of partial vs. full ROM resistance training on muscle size, strength, power, body fat, and sports performance. The duration of the studies ranged from 3 to 16 weeks.

Movement patterns were defined as partial ROM (9°–90°) and full ROM (70°–140°). Most studies (19 studies) examined partial ROM at short muscle lengths (i.e., the muscle length during partial ROM was lower than during the full ROM), while only a few studies used moderate (1 study) or long muscle lengths (6 studies). Notably, a certain amount of ROM was deemed a “full” ROM, regardless of what each individual participant’s full ROM truly was. Only a few studies individualized the ROM used to the individual’s full ROM.

A subgroup analysis was conducted to investigate whether the outcomes would differ depending on the outcome (muscle size, strength, and power), trained muscle groups (upper vs. lower body), outcome bias (outcome biased toward a partial or full ROM), resistance training modality (machines vs. free weights vs. both combined). and the type of partial ROM exercises (conducted at short vs. long muscle lengths).

Moreover, the researchers conducted a meta-regression analysis to investigate the effects of various moderating factors on the outcomes, including the intervention duration, the participants’ height, time under load, and proportion of sets done with a full ROM.

Both full and partial ROM had similar effects on muscle size, strength, body fat, and sports performance. However, full ROM was more effective for enhancing power outcomes (small effect size. The evidence quality was rated as moderate for muscle size, strength, and power and high for body fat and sports performance.

The effect of partial vs. full range of motion on study outcomes

The participants’ height had a minor influence on outcomes, with taller individuals benefiting more from full ROM. Moreover, there was a trend toward greater effectiveness of partial ROM at long muscle lengths for muscle hypertrophy, though this effect was not statistically significant.

Partial vs. full range of motion: select differences

Outcome bias also played a role, with studies biased toward full ROM showing some benefits for this approach.

ROM is a cornerstone concept in resistance training, yet its optimal use — particularly the question of full versus partial ROM — is heavily debated among fitness enthusiasts and the scientific community. To shed more light on the optimal use of this key aspect, the researchers conducting the summarized study undertook a meta-analysis of various randomized controlled trials to compare full and partial ROM across a range of outcomes.

Initially, the study’s primary outcome may appear underwhelming: both partial and full ROM were equally effective in enhancing muscle hypertrophy, strength, body fat management, and overall sports performance. Contrary to expectations, partial ROM demonstrated a comparable effectiveness to full ROM. This finding challenges the long-held belief in the superiority of full ROM, showing that partial ROM can elicit similar physiological responses. Notably, though, most outcomes showed a slight preference for full ROM, positioning it as a potentially effective "default strategy" for many athletes.

Moreover, one distinct advantage of full ROM emerged in the area of power development. The study found a small benefit of full ROM over partial ROM on power, a crucial element in athletic performance that hinges on the synergy of force and velocity. Full ROM training, by engaging a wider range of muscles and joints, may enhance neuromuscular coordination and motor skills development, which are vital for activities requiring explosive strength. As such, neuromuscular coordination refers to the ability of the central nervous system to control muscles in harmonized and precise movements, which might be trained more thoroughly using full ROM. Moreover, full ROM training also aids in the development of motor skills by challenging the body to maintain control and stability throughout the entire range of a movement. This is particularly beneficial for athletes who participate in sports requiring sudden bursts of power, such as sprinting, jumping, or lifting. Overall, the study’s observation that full ROM is superior for power development resonates well with the fundamental principles of exercise physiology.

Despite these general advantages of full ROM, there was one notable exception: partial ROM at longer muscle lengths showed a tendency for better muscle hypertrophy outcomes compared to full ROM. This observation aligns with previous research, suggesting that longer muscle lengths during partial ROM exercises can lead to enhanced muscle growth.^[1] One possible explanation for this finding might be an increased passive tension, leading to the activation of growth pathways.

Passive tension is borne by a muscle when it is lengthened beyond slack length. As passive tissues within the muscle reach their maximal length, they begin to provide resistance to further stretching, generating this passive tension. Notably, this tension is thought to activate the mammalian target of rapamycin complex 1 (mTORC1) pathway, which plays a pivotal role in muscle hypertrophy. The mTORC1 pathway is a critical cellular mechanism for muscle growth, responding to various stimuli, including mechanical tension. Increased passive tension from exercises performed at longer muscle lengths could enhance the activation of this pathway, thereby promoting greater muscle hypertrophy compared to exercises performed at shorter muscle lengths. This concept aligns with emerging research suggesting that stretch-mediated hypertrophy — a process characterized by muscles growing in response to being stretched — is significant in humans. For example, a previous study demonstrated that the gastrocnemius muscle (i.e., the large muscle on the posterior calf of the leg) exhibited substantial hypertrophy following extended periods of stretching.^[2]

In sum, the study reveals that the influence of ROM on resistance training outcomes is relatively minor. The choice between full and partial ROM should be tailored to individual goals and circumstances, such as in cases where injuries preclude full ROM exercises or based on personal preference. This approach resonates with the principle of specificity, recommending that training should mirror the ROM used in the desired performance outcome, as seen in sports like powerlifting. Overall, the summarized study underscores the need for personalized training programs in resistance training, although future research could potentially revise these findings as general understanding evolves.

This study’s findings should be considered in the context of its limitations. First, the researchers conducted various exploratory analyses, meaning that these analyses were not planned prior to the study. This practice reduces confidence in the results because the observed benefits might equally be explained by coincidence. Second, the duration of the interventions was relatively short and the sample size was relatively small compared to the number of outcomes assessed. Finally, when the researchers only analyzed studies with no outcomes bias, the benefits of exercising with a full ROM vanished. In contrast, studies with a strong outcome bias toward a full ROM also showed a stronger effect for exercising with a full ROM. In other words, outcome bias might also explain the observed benefits of full ROM in certain instances.