The MyoTruk offers significant advantages over traditional exercises typically used to develop leg strength for rugby. It aids in the training of specific muscle/joint actions, rapid adoption of sound technique, avoidance of lower back overload and encourages persistence with the exercise program.
In scrummaging the typical movement of both hip and knee joints is from 90° to 120°-130° of extension (full extension being 180°). In the past there have been three common multi-joint exercises used to train hip and knee extension. These are barbell squats, barbell dead-lifts and the leg-press.
The barbell squat is often referred to as the 'king of exercises' but it is one of the least popular and most frequently avoided exercises.
At the bottom of the squat movement there is a large amount of shear force about the discs of the lower back and structures of the knee due to the direction of loading compared to torso and limb alignment. With vertical loading on a forward tilted torso it is difficult to display good form. Balance problems or lack of abdominal strength can produce poor technique and an inability to progress in the exercise or worse still, cause injury.
With barbell dead-lifts this type of shear force loading is even more pronounced causing not only accentuated forward tilting of the torso but also flexion of the lower lumbar spine which can cause injury when even moderate loads are lifted.
Due to the inherent need for exemplary technique to be learnt before the squat and dead-lift become viable training movements (which can take a whole season or longer) the leg-press is often substituted because of its lack of risk to the lower back. However, with the seated leg- press the hip joint range of movement is only between 40°-90° extension, which is dysfunctional for the purpose of training muscle movement for scrummaging.
Thus traditional gym-based exercises used for hip/knee extension are either difficult to learn with harsh loading patterns for the lower back or they are not functional for the all-important hip drive. By contrast the MyoTruk exercise position is natural and loading on the lumbar region is mostly straight line (compressive) without an appreciable shear component.
This ease of technical mastery and user-friendly operation encourages continued use of MyoTruk even during the playing season when compliance to other leg exercises, especially squatting, is traditionally very poor.
The fully extended position illustrates the unique benefits derived from exercising with the ScrumTruk. As the athlete approaches complete extension, the hip and thigh extensors are under full loading due to the increasing resistance provided by the QuadTorq technology. Note also the very obvious activation of the gastrocnemius and soleus muscles of the calf.