Dr. Fin Biering-Sorenson, a Danish spine expert, found that the key to preventing lower back pain is to build up “isomeric endurance”.
The ability of the lower back muscles to maintain moderate levels of force … for prolonged periods… without significant fatigue.

In the British Military, we used this test as an objective marker for non-specific lower back pain. Of all the tests we used, this one was the most effective as a predictor of lower back pain re occurrence. I would like to share this test with you so that your athletes can benefit.
In 1984, following a study by Biering-Sorensen in Denmark, a new test was designed for evaluating the isometric endurance of trunk extensor muscles. This became known as the “Sorensen test” and gained considerable popularity as a tool reported to predict low back pain within the next year in males. The test consists in measuring the amount of time a person can hold the unsupported upper body in a horizontal prone position with the lower body fixed to the examining table:
To build up your client’s isomeric endurance and Bulletproof their back:
1.     Lie them face down on a bench and strap their legs or sit on their legs if they are OK with that.
2.     Their legs should be supported by the bench with their upper body extended over the edge.
3.     Keep their upper body parallel to the floor, with their arms folded against their chest, for as long as they can.
Repeat this test regularly until they have built up enough endurance to maintain a horizontal position for 120 seconds or 2 minutes.
Although its discriminative validity, reproducibility, and safety seem good, debate continues to surround its ability to predict low back pain; in addition, the gender-related difference in position-holding time remains unexplained and the influence of body weight unclear. A contribution of the hip extensor muscles to position holding has been established, but its magnitude remains unknown. The influence of personal factors such as motivation complicates the interpretation of the results. Despite these drawbacks, the Sorensen test has become the tool of reference for evaluating muscle performance in patients with low back pain, most notably before and after rehabilitation programs.

The Biering–Sorensen test provides reliable measures of position-holding time and can discriminate between subjects with and without nonspecific low back pain (Latimer et al, 1999). The influence of motivation and effort exerted by the subject are limiting factors in all of the tests reviewed. These psychological factors warrant further research. . On the basis of the literature reviewed, we determined that the Sorensen is probably the most clinically useful of these tests; it is easy to perform, requires no special equipment, and enjoys the most support from the literature. (J Manipulative Physiol Ther 2001;24:110-22)
References

Latimer et al, (1999) The Reliability and Validity of the Biering–Sorensen Test in Asymptomatic Subjects and Subjects Reporting Current or Previous Nonspecific Low Back Pain. Spine: 15 October 1999 – Volume 24 – Issue 20 – p 2085

Moreau et al (2001) Isometric Back Extension Endurance Tests: A Review of the Literature J Manipulative Physiol Ther; 24:110-22)

Video: https://www.youtube.com/user/movementskill