There are three body types which determine what kind of workouts will be most conducive to your goals. These three body types are endomorph, ectomorph and mesomorph.
Endomorphs are identified by the dominance of soft roundness throughout the body, which could be a result of a chronic condition or even just a naturally slow metabolism. Endomorphs typically gain fat fast and struggle to lose weight. They have a stocky bone structure with large hips and midsections.
Endomorphs should focus training on cardiorespiratory techniques and fat loss while maximising calorie burn with the use of high-intensity workouts. While also maintaining regular aerobic and anaerobic exercise. If this is your body type, you usually have to work much harder to reach your fitness goals and should try and keep active even outside the gym and consume a diet high in protein with balanced fats and carbs.
Ectomorphs usually appear lanky, with narrow hips and shoulders in respect to their height. They also typically have smaller muscles and a fast metabolism which makes it difficult for them to gain weight.
When it comes to training, they are the opposites of endomorphs and should focus on maximising muscle gain by using low-intensity workouts with more extended resting periods in between. Prioritise hypertrophy and maximal strength training, which are both primarily anaerobic, while maintaining a diet high in protein with balanced carbs and fats.
Mesomorphs typically have a medium bone structure, with shoulders wider than their hips. Their bodies are predominantly composed of muscle, bone and connective tissue, making them appear athletic in nature and rectangular in shape. The naturally athletic build of a mesomorph is the result of activity throughout their lifetime. Mesomorphs tend to have an extremely efficient metabolism which allows them the ability to gain mass and lose weight with relative ease.
As a result of their highly effective metabolisms, workouts can be made specific to their own fitness goals. Similarly, the diet must then adhere to those particular fitness goals, by either increasing or decreasing your protein intake.
It is important to note that your body type is not a life sentence, and you can work on the goals you have set for yourself. However, knowing your body type allows you to make the changes you need to to reach your goals much more effectively.