I’ve spent the last 20 years reading the scientific literature pertaining to all modes of exercise. Although the research has shifted my understanding and approach to exercise significantly over the years, one element has continued to emerge from this research: the importance of supervision in strength training.
A sampling of studies examining a variety of populations yield a similar outcome: Supervision produces better results.
A 2000 study published in Medicine and Science and Sport and Exercise concluded, “Directly supervised, heavy-resistance training in moderately trained men resulted in a greater rate of training load increase and magnitude which resulted in greater maximal strength gains compared with unsupervised training."
A 2004 study published in the Journal of Strength and Conditioning Research that utilized collegiate rugby players as subjects concluded, “The present findings provide strong support for the direct supervision of resistance training in young athletes. In the practical setting, the direct supervision of resistance training by appropriately qualified strength and conditioning coaches will significantly augment the absolute strength and percent increases of supervised athletes when compared to unsupervised athletes.”
A 2009 study published in Epidemiology and Clinical Medicine examined the impact of supervised exercise versus non-supervised exercise in overweight adults. Researchers concluded that, “Exercise under supervision of a qualified fitness instructor leads to a larger decrease (in fat mass).”
A 2011 study conducted in the Netherlands comparing supervised and unsupervised strength training concluded, “After four months, those who received supervision lost more weight (17.6 pounds compared with 6.16 pounds) and body fat (13.64 pounds compared with 3.74 pounds) than those who received no supervision.
In research studies, two separate groups who perform the exact same workouts will have dramatically different results when one group has direct supervision. Regardless of the type of exercise, the style of the workout, or the goals of the individual performing the workout (a type-2 diabetic or an elite athlete), the singular element of direct supervision always produces better results.