Did you know that when compared to other commonly used exercises in hamstring rehabilitation, The Tantrum (AKA Fitball Flexions) has one of the highest levels of hamstring recruitment? Even more than the Nordic Hamstring exercise!! (Tsaklis et al, 2015).
The only thing to consider is that the highest level of activity is when the muscle is SHORTENING, which is not particularly useful as most hamstring strains occur when the hamstring unit is LENGTHENING.
THE SITTING TANTRUM VARIATION
So as a stand-alone exercise, the Tantrum is not that useful for injury prevention. However when added to a comprehensive program, it can be a very powerful exercise to help improve hamstring muscle recruitment and performance.