Whilst walking out and about, what is happening with your arms? Are you holding on to something? A handbag? Shopping? Another person? Or, are your arms swinging alongside you?
Reciprocal arm swing is what your arms are doing when you allow them to move during walking. It is part of the gait cycle. Your body twists from side to side during this cycle and our arms swing to help counter balance the twisting action of the pelvis and the thoracic spine (think rib cage area).
Go for a walk now and see what happens. If you keep your arms still alongside your body whilst moving, your body will rotate from one side to the other in an almost robotic fashion. If you allow your arms to move, your torso stays facing straight ahead. In this scenario, you have the opposite side arm and leg moving forward and the other moving back.
Allowing your arms to swing is also the perfect antidote for ‘tuck shop arms’ otherwise known as ‘bingo wings’. So many people have asked me over the years, "What can I do to tone my arms?" Swing them. You can practice without even having to walk. Simply stand in place and start with just one arm. Push it backwards and allow it to swing forwards on its own. Feel how the back of the arm has to work to achieve this motion. Then try it with both. Then try it moving.
What about people with arms that swing across the body? This is a case of internally rotated arms at the shoulders. These people have often spent many hours in positions which draw their shoulders forward and rounded, such as typing, driving and washing dishes. They can benefit by doing exercises such as snow angels.
Snow angels are great because they can be done on the floor, on a foam roller or bolster and even against the wall. In supine position (stomach up) open your arms out to the sides and keeping the ribs and tail down, slowly move your arms towards your feet. Then reverse direction taking them over your head as far as they go without hiking your shoulders around your ears. Repeat.