Deadlift on straight legs
Upper hamstring, buttocks and extensor spine / Basic exercise / Mass, shape, separation of the thigh and buttocks
Technique
Stand behind the bar with your feet under the bar. Put your feet slightly wider than your shoulders. Push your hips back and grasp the bar with an overhand grip wider than shoulder width. Raise the barbell and fully straighten up: the chest is straightened, the shoulders are laid back, the back is slightly arched in the lower back.
Take a deep breath and, holding your breath, bend over, simultaneously pulling your pelvis back and keeping the arch in your lower back.
The bar descends and rises strictly in a vertical plane. The hands are almost relaxed and serve only as ropes, to the ends of which the barbell is attached.
Having reached the bottom point of the exercise (the torso is parallel to the floor or slightly lower), do not exhale! Still holding your breath and keeping your lower back arched, push your pelvis forward and lift your torso. Exhale, overcoming the most difficult part of the lift.

Tips

The bar descends and rises straight up and down (rather than sliding along the surface of the legs), as if it is hanging freely on your shoulders – this is the only difference between the deadlift on straight legs and the Romanian rise.
Even though the straight-legged deadlift forces both the hip extensor muscles and the spinal extensors to full strength, the main goal of the exercise is the muscles of the back of the thigh and buttocks. Only they are subject to dynamic contraction (i.e., they shorten when the hip joint is extended). The muscles surrounding the spine act only as stabilizers and contract isometrically, counteracting the flexion-extension of the spine, and keep its natural, S-shaped curve unchanged. Don’t tense your press.
Don’t round your back. If you feel that you can’t keep the arch in your lower back, it’s better to stop, even if the torso has not yet reached parallel with the floor.
To achieve maximum contraction of the buttocks and muscles of the back of the thigh, keep your legs straight and locked at the knees. Flexion-extension of the legs during movement is unacceptable.
Hold your breath for a while “bend-straightened” – it’s easier to keep the deflection in the lower back.
Do not pull the barbell with your hands (pulling your shoulders back) or your lower back (trying to bend at the spine during the lift). Focus only on hip extension – pull the pelvis forward and do not allow the spine to bend and unbend.

Deadlift on straight legs наращивает массу верхней половины мышц задней части бедра и ягодиц, подтягивает низ ягодиц, утолщает верх и середину бицепса бедра, а также укрепляют мышцы, окружающие позвоночник.

The more powerful the force generated by the muscles of the back of the thigh, extending the hip joint, the stronger you push your foot off the ground and the greater the acceleration of the body while running or jumping. And, as you know, it is the initial acceleration of the body that directly determines the speed of running, the height and length of the jump.