December 2022 / January 2023 / February 2023 | Akwa | 9 Then, while driving, I almost hit a biker who glided through a stop sign and turned in front of me. While replaying that event in my mind afterward (as we do with upsetting things), I realized that the biker didn’t want to stop because it takes more energy to stop and restart than it does to keep going. I decided I’d try it in the pool, and it turns out Newton was right! With something as basic as walking forward and back- ward, if we stop and restart, it’s much more challenging. The energy cost increases, the muscles must be re-recruited (no momentum), and the effort in the core (if the stop is com- plete) is incredible. The client should stop the body completely. • Arms, especially, should stop. We all tend to use our arms in the water for balance. Flailing arms won’t help during a fall on land. • Clients shouldn’t have to take another step to stop and find balance. • The core should engage during the ‘stop’ so the hips/torso don’t have to bend and torque. • The head shouldn’t have to move at all. Similarly, there should be attention during the restart. • Clients should try to restart without using their arms. It’s hard, but it’s excellent for core and alignment. • The torso should be able to stay upright, not lean into the movement. • The head stays in alignment rather than using neck flex- ion to begin the movement. Newton’s first principle states that a particle left to itself has constant velocity; said differently, inertia is the tendency of masses to resist changes in motion. A mass at rest tends to remain at rest; a moving mass tends to remain in motion at a constant speed unless acted upon by an outside force - to overcome inertia, a force must be applied. Consider using force to overcome inertia to alter the intensity of an exercise. By using fewer repetitions, moving through the water, and changing direction, the exerciser increases the intensity by repeatedly applying force to overcome inertia. Conversely, if they do several repetitions of the same move- ment, stay in place, or keep the movement facing in one direction, intensity decreases by minimizing the need to use force to overcome inertia. One specific example of the use of inertia is changing steps frequently to increase the outcome of a session. For exam- ple, four walking steps followed by four knee lifts would require more energy than eight walking steps followed by eight knee lifts. This is because once walking has started, the body (mass) wants to continue the movement unless a force acts upon it. Therefore, more frequent changes require more energy. There are three different types of inertia: (1) stationary iner- tia, (2) moving inertia (momentum), and (3) inertia lag (drag or friction). Beginning from a motionless position in the water, the client will have to overcome stationary inertia. When the client is already moving and needs to continue to exert energy to keep moving, they are overcoming moving inertia. Inertia lag refers to the loss of forward momentum and requires extra energy to increase the forward momen- tum again. No matter the water depth or pool temperature or the age and ability of your client, I think you’ll find some great ben- efits from these three progressions. EDITOR’S NOTE This free 9-minute video from Ruth Sova covers Heavy Concept, Stop/Start, and Slow Motion. https://vimeo.com/ 638243918 n Author Ruth Sova, MS, is the Director of Education for ATRI and an internationally recognized leader in the aquatic ther- apy industry. Dedicated to the growth and betterment of the industry through her development efforts, Ruth educates and energizes audiences with her presenta- tions on personal growth, entrepreneurship, aquatic therapy-fitness, and business development. She has founded six successful businesses and holds numerous awards and honors. GET OFF Use the code on checkout NEK10 $10 www.nekdoodle.com
