Muscles help the body move, maintain posture and produce force. Almost every exercise a trainer teaches is, at its core, a way of challenging muscles. This lesson explains how muscles work together and why understanding them improves exercise selection and technique.
Three jobs of muscles
Muscles help the body move, maintain posture and produce force. These three jobs show up in everyday life: walking and lifting involve movement and force, while standing upright for hours relies on postural muscles.
- Movement: muscles pull on bones to create motion at the joints.
- Posture: muscles continuously hold the body upright against gravity.
- Force production: muscles generate the force needed to lift, push, pull or resist.
Muscle groups work together
Different muscle groups work together during exercises such as squats, lunges, push-ups and rows. No exercise uses just one muscle. Understanding this helps you coach whole-body movement rather than isolated parts.
Muscle groups in the syllabus exercises
- Squats: mainly use the muscles of the thighs and buttocks, with the trunk muscles helping to stay upright.
- Lunges: use the muscles of the thighs and buttocks, with extra demand on balance and stabilising muscles.
- Push-ups: mainly use the chest, shoulders and the back of the upper arm, while the trunk muscles hold the body in a straight line.
- Rows: mainly use the muscles of the upper back and the front of the upper arm.
Why understanding muscle actions helps
Understanding muscle groups and their actions helps trainers select suitable exercises and maintain proper movement techniques. When you know which muscles an exercise is meant to work, you can notice when other muscles are taking over, a sign that technique or load needs adjusting.
It also helps you build balanced programmes. A client who only trains the chest and front of the body, for example, may need more attention to the upper back to keep the body balanced.
Teaching muscle awareness
Encourage clients to feel the target muscle working. Short, clear cues such as ‘push the floor away’ or ‘squeeze your shoulder blades together’ connect the client’s attention to the correct muscles and improve technique.
