Pushing a heavy leg press machine makes the outer part of your thigh muscle grow more than doing leg extensions, because it puts more overall stress on that part of the muscle.

If you want to grow the outer part of your thigh (vastus lateralis), leg presses might be more effective than leg extensions.

Doing calf raises with your knees straight (standing on toes) makes the inner part of your calf muscle grow more than doing them with your knees bent (seated), because the muscle is stretched more.

Doing leg extensions (kicking your leg out while sitting) makes the front thigh muscle right above your knee grow more than doing leg presses (pushing a heavy platform with both legs).

The outer part of your calf and the deeper calf muscle don’t grow better with either straight-knee or bent-knee calf raises — they respond similarly to both.

If you're a guy new to lifting and you start your workout with big compound moves like the bench press instead of isolation exercises, your chest muscles grow more—probably because you're not too tired when you do the main exercise.