What You'll Get
Choose Between Two Options
- $36 for a 45-day gym membership ($92.50 value)
- $70.50 for three personal-training sessions ($180 value)
Building Muscle: Cells on the Move
Read on to learn exactly how fitness classes leave you with more muscle or better tone.
Bulky upper-body muscles might have hindered early humans who had to chase their prey across the plains, but it could help those who often had to climb trees to adjust their satellite dishes. That’s why the body builds muscle according mostly to use: do enough curls, and the biceps expand. As anyone who has experienced post-workout soreness could intuit, those curls are actually a form of controlled damage, making thousands of miniscule tears to the muscle tissue that beckon autoimmune cells to show up alongside testosterone and other hormones. The white blood cells help switch on satellite cells, which are similar to stem cells. Before they’re activated, satellite cells aren’t doing much—instead, they lie dormant around muscle fibers until they’re called into action to repair torn tissue.
This isn’t the only kind of cellular transformation at work in growing muscles. Long muscle cells, which contain several nuclei, can also begin to change type after a workout. Certain kinds of muscle fibers are equipped to handle brief bursts of effort but will quickly become tired if asked to do more intense work. These are the first to disappear as someone starts an exercise routine, as they’re converted into fibers with more endurance. This principle is so dramatic that a sports scientist can generally tell whether someone is a professional athlete or a professional mattress model by examining a minute sample of muscle tissue.
The Fine Print
Promotional value expires 180 days after purchase. Amount paid never expires. Current members or those who have been back within 12 months are not eligible. Limit 1 per person, may buy 2 additional as gifts. Valid only for option purchased. All goods or services must be used by the same person. Limit 1 pack of personal training per person. Must be 21 and over. Only valid at listed location. Personal training sessions have a 3 month expiration. May be repurchased every 30 days. Merchant is solely responsible to purchasers for the care and quality of the advertised goods and services.