The best exercises for building strength and muscle are multi-joint movements using bodyweight, leverage and either bands or free weights for loading.
These multi-joint movements involve balancing and stabilization which recruits more muscle mass and has a stronger impact on your nervous and hormonal systems resulting in greater strength and muscle gains.
They are natural movements using resistance that moves freely so the path of movement is determined by the levers of your own body rather than the track of a machine. Therefore your movement is congruent with your own structure so that you have a lower risk of injury.
Elastic Strength programs emphasize using closed chain movements wherein you move your body. By choosing exercises that use your bodyweight for a significant or large portion of the resistance you can impose large demands on your muscles with lower external loads and reduced risk of spinal injury.
Squatting exercises are the best way to build strength and muscle in the hips and quadriceps (front thighs).
Back arch ups and standing band leg curls are the safest widely available exercises for building strength and muscle in the lower back and hamstrings (posterior chain).
The standing rise on toes is the best exercise for developing the strength and muscle mass of the calves.
Handstands and the standing overhead press are the best vertical pushing exercises for developing the strength and muscle mass of the shoulders – deltoids and trapezius – and they also develop the triceps of the upper arm.
Supinated grip pull ups (a.k.a. chin ups) are the best vertical pulling exercises for developing the strength and muscle mass of the upper back and biceps.
Dips and push ups are the best horizontal pressing exercises for developing the strength and muscle mass of the pectoral muscle of the chest as well as the triceps of the upper arm. X3 chest presses are the best alternative to these superior bodyweight based exercises.
The fulcrum 90º /sternum pull up is the best horizontal pulling exercise for developing the strength and muscle mass of the upper back and biceps. The inverted rowing exercise is the best alternative for people who can't yet perform the fulcrum 90º /sternum pull up.
Neck extensions and neck flexions are the best exercises for developing the strength and muscle mass of the neck.
V-ups, side arch ups and windshield wipers are the best exercises for developing the strength of the anterior and lateral muscles of the waist.