Rowing Biomechanics: Technique Changes with an Increase of Power Demand

The sport of rowing has become more popular in the past decade. While it is a relatively low impact sport, injuries can occur, specifically to the ribs (Karlson K. A., 1998) and more often in female athletes (Hickey, Fricker, & McDonald , 1997). It has been proposed that as the athlete rows, applying a cyclical load to the body, the mid trapezius fatigues and is unable to resist the force produced during the drive phase (Warden S. J., Gutschlag, Wajswelner, & Crossley, 2002). Once this happens, the scapulae are then pulled anterio-laterally which increases the compression force on the ribs, increasing the risk of injury. The rowing motion of 12 female varsity and club rowers was tracked as they completed a fatiguing rowing test on a rowing ergometer. Results showed that the curvature of thoracic spine changed throughout the rowing cycle but did not change with increasing power level. The transverse shoulder angle decreased (the upper back was less straight) as power level increased (R2=-0.69±19), suggesting that the scapula moved anterio-laterally. This may be that as it tired, the mid-trapezius was unable to hold the scapulae in position. The decreasing transverse shoulder angle when the power level is increased indirectly supports the fatiguing of the retractor muscles as a mechanism of injury. It would be valuable to understand the limitations of each athlete and to be able to prescribe the optimal training zone to reduce the risk of injury.

Vicarious Power: The Interpersonal Transference of Power

Thesis (Ph.D, Psychology) -- Queen's University, 2016-07-29 15:58:26.695

The Use of Nudges in Exergames to Moderate Player Exertion

Exergames are digital games with a physical exertion component. Exergames can help motivate fitness in people not inclined toward exercise. However, players of exergames sometimes over-exert, risking adverse health effects. These players must be told to slow down, but doing so may distract them from gameplay and diminish their desire to keep exercising. In this thesis we apply the concept of nudges—indirect suggestions that gently push people toward a desired behaviour—to keeping exergame players from over-exerting. We describe the effective use of nudges through a set of four design principles: natural integration, comprehension, progression, and multiple channels. We describe two exergames modified to use nudges to persuade players to slow down, and describe the studies evaluating the use of nudges in these games. PlaneGame shows that nudges can be as effective as an explicit textual display to control player over-exertion. Gekku Race demonstrates that nudges are not necessarily effective when players have a strong incentive to over-exert. However, Gekku Race also shows that, even in high-energy games, the power of nudges can be maintained by adding negative consequences to the nudges. We use the term "shove" to describe a nudge using negative consequences to increase its pressure. We were concerned that making players slow down would damage their immersion—the feeling of being engaged with a game. However, testing showed no loss of immersion through the use of nudges to reduce exertion. Players reported that the nudges and shoves motivated them to slow down when they were over-exerting, and fit naturally into the games.