In recent years, "science-based" lifting has seen a remarkable resurgence, marking a transition in the landscape of modern bodybuilding. With the dominance of social media, bridging information between both professional bodybuilders and amateur “gym-goers”, the availability of training information has never higher. However, what seems like a newfound phenomenon traces its roots back to the 1980s with legendary bodybuilder Mike Mentzer. He introduced his own form science-based training which was starkly unconventional: low-frequency, high-intensity training—a mere 30 minutes per day, three to four times a week. It was nothing short of radical, considering how near all of his competition trained hours upon hours a day, everyday of the week. While subsequent research in recent years has challenged some of Mentzer's approach, his scientific methodology laid the groundwork for the "optimal training" philosophy.
Since Mentzer’s time, research in hypertrophy training has exploded, unveiling new techniques to maximize muscle growth. Recently, a study led by Jeff Nippard, arguably the most popular content creator for science-based lifting, explored the efficacy of a technique known as "lengthened partials." This method, while recently popularized, has actually been a staple among greats like Tom Platz, whose quadricep training incorporated lengthened partials on the hack squat and leg extension machine. Lengthened partials focus on training a muscle at its lengthened position, utilizing a fraction of the range of motion (ROM) where the moment arm, or lever distance, is at its peak distance. This technique, applicable to any movement pattern, is founded on the scientific principle that greater muscle tension at the lengthened portion of a movement causes more micro-tears in muscle fibres that, once repaired, stimulate greater hypertrophy compared to its non-lengthened counterpart. In other words, the “stretch” portion of a movement results in a greater increase of muscle mass than the “contracted” portion. Despite theoretical proof, lengthened partials had yet to undergo any rigorous testing in a real-world setting until Nippard’s study.
Nippard, alongside researchers from the Applied Muscle Development Laboratory at CUNY Lehman College, aimed to determine what constitutes an optimal technique for hypertrophy. Emphasizing the value of full ROM and repetition tempos within a 2–8 second range, they proposed that longer muscle lengths during partial ROM may be superior for hypertrophy.
However, optimal RT technique is not universally defined, as one’s individual goals influence what is considered "proper form." For example, an olympic lifter’s benchpress technique would emphasize the shortest ROM to maximize intensity capacity. Whereas a bodybuilding might extend ROM to beyond parallel depth to reach tension below chest level. Therefore, the study only suggested guidelines for foot placement, grip width, and body alignment in accordance to biomechanical principles and empirical research linking specific kinematic adjustments. While these variable may differ between participants of the study, they recommended a focus on maintaining eccentric phase control and full ROM to maximize hypertrophic outcomes.
The study investigated repetition tempo, an often controversial topic within science-based lifting. While slower eccentric tempos are widely accepted to promote larger muscle growth, the study found that tempos within a broad range (2 to 8 seconds) generally produce comparable hypertrophy results. While some evidence favours slower eccentrics with faster concentrics for hypertrophy in specific muscle regions, the literature remains inconclusive on an “optimal” tempo. As a result, it was found that an emphasis on eccentric control rather than a strict duration is more optimal for enhancing muscle stimulation.
The most significant finding was the role of ROM in hypertrophy. Traditional evidence suggested that full ROM was optimal, but the study showed that partial ROM exercises at long muscle lengths may actually yield superior gains for certain muscles. Most notably, training at the lengthened position appears more effective for distal hypertrophy. Compared with other recent studies, lengthened partials seem to maximize hypertrophic gains in muscles like the quadriceps, hamstrings, and gastrocnemius. This finding reinforces the effectiveness of lengthened partials, particularly when paired with a controlled eccentric ROM.
The final aspect of optimal technique that was studied involves exercise-specific kinematics. Namely, how one’s body positioning and movement patterns influence the effectiveness of a given exercise. While guidelines such as even weight distribution are based on a biomechanical reasoning, the real world impact of kinematic variations on hypertrophy remains uncertain. The study analyzed strict vs. non-strict techniques, cautioning that involving unintended muscle groups (e.g., using hip extensors during a bicep curl) could possibly detract from potential hypertrophy by shifting the load away from the targeted muscle. Conversely, moderate momentum may sometimes enhance hypertrophy by enabling a heavier stimulus. However, Nippard ultimately recommends minimizing any involvement of ancillary muscles while performing a movement.
In accordance with his findings, Nippard recommends, in order to maximize muscle growth:
While the bodybuilding world has certainly changed, it's enlightening to see that traditional training principles have a proven scientific grounding. Techniques like lengthened partials, once practiced intuitively by the bodybuilding legends of the past, are now validated through emerging research. As we continue to unravel the perpetual complexities of hypertrophy, the future of “science-based” lifting holds exciting possibilities.