Smith machines are heavy metal frames consisting of a barbell and a series of weighted plates. You can perform numerous exercises with a Smith machine, including the good-morning lift. Performing good-mornings on a Smith machine is advantageous because the the barbell follows a track, reinforcing a smooth, controlled movement. Smith machines are also equipped with safety catches that prevent the barbell from falling on your back if you lose your grip.
Smith Good-Morning Technique
The Smith good-morning exercise is performed by first setting the barbell at a height just above the shoulders. Begin this lift by placing the bar on the back of your shoulders. Lift it off the racks by rotating the bar backwards. Bend your hips forward, keeping your legs and spine straight. Lower the weight toward the floor in a smooth manner and stop when your torso is parallel to the floor. Slowly return to the starting position.
Target Muscles
The hamstrings are the primary muscles targeted in the Smith good-morning exercise, says ExRx.net. As the weight is lowered to the floor during the eccentric phase of the lift, the hamstrings lengthen and slowly bear the majority of the load. The hamstrings shorten as the weight is returned to the start position during the concentric phase.
Synergists
Synergists are muscles that are not directly involved in controlling a lift, but supplement the movement indirectly, notes the National Strength and Conditioning Association. Both the gluteus maximus, or buttocks, and the adductor magnus, or groin, are synergists for the Smith good-morning exercise. Synergists provide assistance in producing the same joint motion as the target muscles.
Stabilizers
A stabilizer muscle is one that contracts during a particular lift, but does not move significantly throughout the motion, reports ExRx.net. In the case of the Smith good-morning exercise, the erector spinae, a muscle that supports the entire length of the spinal column, acts as a stabilizer to the hamstrings. One disadvantage to the Smith machine versus a barbell good-morning is that the machine supports the lift and the stabilizer muscles are not allowed to activate fully, limiting this lift's benefit.
Antagonist Stabilizers
Antagonist stabilizers are muscles that support the antagonist muscle, or the muscle that acts in opposition to the target muscle. The rectus abdominus, or central stomach muscle, and the obliques, or side stomach muscles, act as antagonist stabilizers to the hamstrings. The muscles located around the abdominal region and lower back provide support for almost all structural exercises, including the good-morning. Strengthening this region can lead to improved performance and reduced risk of injury, according to the Sports Injury Bulletin.
References
- SepalGym.com: History of the Smith Machine
- ExRx.net: Smith Good-Morning
- "Essentials of Strength and Conditioning"; Thomas R. Baechle and Roger W. Earle (eds.); 2008
- Sports Injury Bulletin: Lower Back Injury Prevention and Lower Back Pain Rehabilitation Exercises
