Bench Press Legs
Even though this might seem like a small difference the impact of having the feet off the floor while bench pressing can change the emphasis of the movement drastically.
Bench press legs. Slowly lie down on the decline bench so your legs are higher than your head keeping your back firmly planted into the back of the bench. The harder you contract your leg muscles the greater the force you exert when driving your legs during the bench press. The legs up bench press is performed like a standard bench press but rather than the feet placed on the floor the legs are bent and the feet are positioned flat on the bench.
In fact over arching the lumbar spine during the bench press is a sure fire way to both injure your low back and eliminate the growth inducing stimulus of the chest press itself. Leg drive in the bench press leg drive is a specialized bench press technique that elite powerlifters use when applying maximum force to the barbell. There are other less direct benefits of squeezing the bench between your thighs.
Bench angled down at 30 degrees. This is a huge advantage because the bench press follows an ascending strength curve. Using the leg drive technique allows lifters to position their torso more effectively on the bench.
Squeezing the bench with your inner thighs activates your leg musculature particularly the adductors hamstrings and glutes more intensely. For example when attempting a 1 rep max lift. The muscle tension needed to move the weight decreases throughout the range of motion such that the lift will typically feel easier as you near full extension.