Study identifies a protein that can either build muscle or aerobic capacity
Scientists in America have identified a new ‘muscle switch’ that influences the benefits of exercise. The team studied rodents and then humans over a period of exercise and discovered that a protein, c-Jun N-terminal kinase (JNK), stimulates the individual’s response to training. If JNK is activated during exercise, it drives muscle growth; if it’s not, muscles improve their adaptation for endurance and aerobic capacity. Key to JNK’s role is its impact on the muscle signalling pathway myostatin, with reams of research showing high levels of myostatin help boost endurance performance; low levels are associated more with muscular force. The team showed that inhibition of JNK increased myostatin signalling, resulting in greater endurance gains. However, levels of JNK varied between subjects, suggesting differences are down to mechanical stress on the muscle. This means while some triathletes might produce high levels of JNK from long, slow runs, others will enjoy greater endurance gains from intervals. Expect DNA companies to add JNK to their genetic list very soon.
If only performance improvement was as simple as flicking a switch – well, thanks to a recent U.S. study, it looks like it finally is!