BRAIN When accelerating, blood is pulled away from the brain and moves toward the lower half of the body. This gives an exciting, but temporary, sensation of light-headedness and exhilaration with a heightening of all senses.
HEAD Together with a helmet, the neck has to support about 4kg, so when riding, neck muscles can get squeezed or pinched, sometimes resulting in a whiplash sensation. Uncomfortable in the short term, and can cause muscles to ache over longer periods. Correcting posture and regular breaks will help prevent this.
HEART During rapid acceleration (or deceleration) the heart can reach 180bpm; 95% of its capacity! This cardio activity is exciting in the short term, but not sustainable over long periods. The body can release adrenaline with the sudden experience of accelerating, heightening the senses.
SPINE During acceleration, forces spread upward through the entire body, compressing the spine. The spine is central to the nervous system and any forces will be felt acutely, alerting the brain to pressures, movements and potential threats.
RIBS & LUNGS When accelerating, G-force pulls the ribs down, emptying the air from the lungs. G-force is what makes flying, fairground rides and motorcycling exhilarating. Being able to precisely modify the G-force with throttle or brakes makes motorcycling a unique experience.
TISSUE Exposure to rapid deceleration can cause tissue deformation, but 'normal riding' will only give brief periods of mild forces - and many riders enjoy the sense of excitement that falls under their own control.
MUSCLES The body tenses and flexes during deceleration, strengthening muscles. It's estimated that riding a motorcycle can burn 300 calories per hour. Riders must not underestimate the need for hydration, frequent intake of light and easily digested food with frequent rest-breaks on longer rides.
INTERNAL ORGANS The sudden stopping of forward movement can be dangerous to your internal organs - liver, spleen, kidneys. There are no risks during normal incident-free riding. During normal deceleration, the fatty tissues and surrounding muscles enable our bodies to cope well with the forces of riding a motorcycle.
EYES Rapid deceleration can cause the blood to pool with great force in the eyes, bursting capillaries and potentially tearing retina. You don't need to worry about this during normal incident free riding.
HEART As with acceleration, during rapid deceleration, the heart can reach 180bpm due to the sudden change in state experienced by the body. After decelerating though, the heart can slow giving a feeling of released tension and ease.