For people who want to increase muscle size and strength, resistance exercise is the way to go. For those who want to increase stamina, endurance exercise is a better option. But what drives the body’s response to these varied forms of exercise? One gene that plays an important role has been identified in a new study.
Coauthor of the study, Heikki Kainulainen from the University of Jyvaskyla in Finland, along with other colleagues, published their conclusions in the journal of Physiological Reports.
What is resistance exercise? It is defined as any activity that causes contraction of the skeletal muscles. Examples include pushups, weightlifting and squats. On the other hands, endurance exercise, also known as aerobic exercise, is defined as any activity that sustains an increase in breathing and heart rate. Examples of which include swimming, walking or cycling.
Each form of exercise has a different affect on the body. Skeletal muscle strength can be improved by resistance exercises, while endurance exercise can enhance general functional capacity.
Researchers hypothesize that because there is such a wide range of the effects of endurance and resistance exercise on the body, there must be several varied processes involved when the body responds to each type of physical activity.
Kainulainen and colleagues mention that attempts have been made to pinpoint single molecules or cascades that might work as primary regulator for regulating exercise –specific adaptations.
Former research has stated that a gene called peroxsiome proliferator-activated receptor-gamma coactivator 1α (PGC-1α) could potentially be involved in the way the body reacts to specific types of exercise. The team endeavored to find out more about the function of this gene in this new study.
PGC-1α isoform production varies by type of exercise
19 physically active men were enrolled to their study and were divided into two groups. One group did 50 minutes of endurance exercise – walking on a treadmill – and the second group did 50 minutes of resistance exercise by doing leg press exercises.
Just before exercise, biopsies were then taken from the men’s thigh muscles, and again 30 and 180 minutes after for analysis by the researchers to determine PGC-1α activity.
Results showed that the gene was stimulated in both kinds of activity, resulting in it producing isoforms called PGC-1α exon 1b’ and truncated PGC-1α. Isoforms are different types of a protein produced from the same gene or from different genes if only a bit of a gene’s code is identified.
It was only endurance exercise that sparked the production of the isoform PGC-1α exon 1a, as observed by the researchers.
Furthermore, the team discovered that endurance exercise triggered genes that stimulated growth of new blood vessels and increased stamina. Although resistance exercise also stimulated growth of blood vessels, it also triggered a gene that stimulates muscle growth.
The team was careful to mention that further studies were needed to affirm the varied roles of PGC-1α isoforms in the body’s reaction to different kinds of exercise.