WEIGHT LOSS EXERCISES

WEIGHT TRAINING

Information: weight loss exercises. Weight training has been shown to be one of the safest high intensity fitness exercises. Studies reveale that weight training possessed one of the lowest rates of injury among strenuous forms of exercise and sport.

Compressive vs Shear Forces

When training the legs and the lower back, lower back injuries are always a concern. At the International Conference of Biomechanics held in July 1995 in Finland , Dr Stuart McGill from the University of Waterloo in Canada , who is a world leader on lower back injuries, outlined some important information (McGill, 1995).

Firstly, the spine is much better at handling compressive forces as opposed to shear forces. Compressive forces occur when the spine is loaded in the purely vertical plane with the vertebrae pushed directly downwards. If standing upright with a barbell on your back in a squat position this is the force exerted on your spine.

Importantly, the back is well suited to handling this type of force and will tolerate a load in the order of 12,000 N (i.e. equivalent to a static load of 1,000 kg) before problems occur. However, the spine is not as well suited to shearing forces. These forces occur when the spine is pulled forward and can result in a slip disc.

If standing in an upright posture the compressive forces are those pushing the vertebrae together in the vertical plane, while shearing forces are those operating in the horizontal plane, tending to force some of the vertebrae forward. The back can only tolerate a shear force in the order of 2,000 N before problems will occur.

Consequently, in any lifting exercise an effort should be made to maximize the compressive component of the load and minimize the shearing component.

Reducing Shearing Forces

For example, in a squat movement if the trunk is upright throughout the lift, the forces will be compressive. However, as one begins to flex the trunk forward the shearing component of the load increases dramatically.

Hence in all lifting activities such as squats, dead-lifts, cleans etc. one must make an effort to maintain an upright body posture throughout the lifts and keep forward flexion movements of the trunk to a minimum.

If individuals are having difficulty in achieving an upright posture in a squat lift then the performance of the squat on a Smith machine, or the use of hack squats or front squats will allow for the adoption of a more upright body posture.

Placing Tension on the Muscles and off the Ligaments

When performing exercises involving lower back support, it is important to adopt a hollowed out back posture. This hollow back posture involves a slight degree of hyperextension of the back and really is the natural position of the back. Indeed you should be in such a posture now as you are reading this article.

To achieve it while lifting, one needs to throw the chest forward, the shoulders back, look upwards and push the buttocks out. Such a body posture should be adopted in all lower back supported lifts such as squats, dead-lifts, cleans etc.

This hollowed out back posture takes the stress off the ligaments of the lower back and places it on the muscles, reducing the likelihood of the occurrence of injury. Several lifts are technically difficult to perform and can be dangerous if performed incorrectly.

• Squats
• Dead Lifts

WEIGHT LOSS PROGRAMS SHOPPING