Have you ever wondered how long it takes to lose muscle strength during
a workout hiatus? Researchers in Denmark wondered, too, and what they discovered might shock you.
Their study, featured in the Journal
of Rehabilitation Medicine (2015; doi: 10.2340/16501977–1961), included 17 young men (aged ~23 years) and 15
older men (aged ~68 years). Prior to the experiment, each subject underwent testing to determine voluntary muscle contraction, “leg work capacity” and lean mass. Each participant then had one leg immobilized for 2 weeks, after which tests were repeated. Next, the men took part
in a three- or four-times-per-week bicycle endurance program for 6 weeks.
So, what did the researchers learn throughout this process?
During the 2-week immobilization,
the younger subjects lost up to a third of their leg strength, which study authors said was equivalent to aging by 40 or 50 years! The older group fared better, losing a fourth of the strength they’d had at the study’s inception. The younger group lost twice as much muscle mass as their older cohorts, the authors added.
The researchers also learned that the 6-week cycling protocol was not enough to restore participants’ muscle strength
and mass to pre-immobilization levels. “If you want to regain your muscular strength following a period of inactivity, you need to include weight training,” explained lead researcher Andreas Vigelsø, PhD.
Perhaps as a warning to training clients, fellow researcher Martin Gram emphasized the importance of avoiding significant bouts of inactivity in the first place. “It’s interesting that inactivity causes such rapid loss of muscle mass; in fact it’ll take you three times the amount of time you were inactive
to regain the muscle mass that you’ve lost,” he said.