9/16/19:
On the Life Fitness or Cybex Total Body Arc Trainer, the question "Why do the handles move in the same pattern as the pedals (‘Same Side Forward’)? Why don’t they move opposite/contralateral?
When walking and running, the arms swing in the opposite pattern of the legs, meaning the right arm swings forward when the left leg swings forward, and vice versa. This is called contralateral movement . This contralateral pattern is passive – the reciprocal motions of the pelvis and shoulder girdle are an attempt to maintain constant angular momentum (since they rotate in opposite directions). This is critical when walking or running to help maintain a balanced, forward-facing posture. Since this movement pattern is passive , it is done without you needing to think about it!
Now, let’s consider an exerciser on a cross trainer. This is an entirely different environment, in part because you have handles available to stabilize the body. When holding onto these handles, there is no compromise to balance like when walking or running unsupported. Because of this, there is no need for the arms to move in the opposite direction as the legs. Thus, the pattern that the moving arms take on a cross trainer is largely arbitrary.
One advantage of Same Side Forward, is that both the arm and pedal are working together (as opposed to opposite). Since they are coupled together, one can easily pull harder with the right arm and exert less force with the same leg because they are working together to drive the pedal . This movement pattern effectively allows the user to transfer work to their upper body without simultaneously increasing the work rate of the legs. Or put another way, the user can more effectively contribute to power output by adding pulling force with the same side handle while the leg is also driving the pedal down and back .
LF Biomechanics Team
Updated: 2019-09-13
When walking and running, the arms swing in the opposite pattern of the legs, meaning the right arm swings forward when the left leg swings forward, and vice versa. This is called contralateral movement . This contralateral pattern is passive – the reciprocal motions of the pelvis and shoulder girdle are an attempt to maintain constant angular momentum (since they rotate in opposite directions). This is critical when walking or running to help maintain a balanced, forward-facing posture. Since this movement pattern is passive , it is done without you needing to think about it!
Now, let’s consider an exerciser on a cross trainer. This is an entirely different environment, in part because you have handles available to stabilize the body. When holding onto these handles, there is no compromise to balance like when walking or running unsupported. Because of this, there is no need for the arms to move in the opposite direction as the legs. Thus, the pattern that the moving arms take on a cross trainer is largely arbitrary.
One advantage of Same Side Forward, is that both the arm and pedal are working together (as opposed to opposite). Since they are coupled together, one can easily pull harder with the right arm and exert less force with the same leg because they are working together to drive the pedal . This movement pattern effectively allows the user to transfer work to their upper body without simultaneously increasing the work rate of the legs. Or put another way, the user can more effectively contribute to power output by adding pulling force with the same side handle while the leg is also driving the pedal down and back .
LF Biomechanics Team
Updated: 2019-09-13