Q: What are the benefits of holding the Arc Trainer handles at different positions? Is it simply that you work a different part of the back?
A: Firstly hand position is just one of several variations of exercise intensity on the Arc Trainer. These include; resistance level, incline level, strides per minute, body position (shifting the body forward at incline levels above 8 increases gluteal activation and shares the work more evenly between quadriceps and gluteals) and finally, hand position on the 770AT.
Muscle activation is essentially dictated by two key variables; Range of Motion (ROM) and line of force. The cross trainer arm is simply a lever – so the lower the arm is gripped, the smaller the movement. This can be useful for those who need to limit the range of motion of the arms or rotation of the spine. Similarly, the higher up the arm is gripped the bigger the range of motion which will challenge the muscles involved more.
In terms of the movement, which is same-side-forward (ipsilateral) if the focus is on the working side (that side which is producing concentric movement at both the lower and upper body) then the action at the upper body is to pull, rather than push. Obviously, the opposing side can contribute with a push from the upper body. Typically it is easier to focus on pulling from the same side as the lower body – this is actually a natural movement when powerful movements are required – consider the movement when climbing a ladder, especially if you envisage stepping up two or three rungs at a time. On one side of the body the leg and arm are moving powerfully in the same direction.
Regarding the grips – the majority of the grip is positioned vertically as this encourages shoulder extension which encourages use of latissimus dorsi and elbow flexors (biceps brachi, brachialis & brachioradialis). These muscles are strong so it is natural that most people will use this movement. The advanced grip at the top of handle allows; a) a bigger range of motion and b) the movement to be varied into horizontal abduction at the shoulder which encourages key contribution from rhomboids minor and major and the mid fibres of trapezius. These are useful postural muscles encouraging shoulder retraction and may want to be specifically targeted – note, they are smaller and less powerful than latissimus dorsi. Because the advanced grip is angled, rather than being entirely horizontal – either shoulder extension or horizontal extension movements (and other angles between these two movements) can easily be performed for greater variety.
Vice President, International Training