The side push-up is an awkward exercise, with a short range of motion. Performing it properly takes practice.
Activating your knee flexors, especially your hamstrings, the assisted inverse leg curl with lat pull-down machine can be dangerous.
Use the incline push-up to activate and strengthen the horizontal pushing muscles of your upper body until you can graduate to the standard push-up.
The frog crunch helps to isolate the rectus abdominis and obliques by reducing the contribution of the hip flexors.
The hanging leg raise, an isolated pulling exercise, targets the hip flexors while isometrically working the rectus abdominis and obliques.
Work the upper chest (clavicular pectoralis major), anterior shoulders and triceps using the decline push-up, a compound upper-body exercise.
The lunge is a brilliant exercise, helping you to develop coordination, balance, and the unilateral (one-sided) functional strength of your lower body.
If you don't have access to a leg curl machine, try the inverse leg curl on lat pull-down machine, an isolated pull exercise that targets your hamstrings.
Use the frog crunch with leg raise, a compound core exercise, to activate and strengthen both your abdomen and hip flexors.
The decline crunch is an isolated pull exercise that targets your rectus abdominis. Your internal and external obliques act as synergists.
The superman push-up is an advanced bodyweight exercise that’s great for strengthening your core. Do not use it if you can't keep your core tight.
The bent-knee oblique v-up is an intermediate core exercise that targets the obliques and synergistically works several other core and leg muscles.