Influence of Arm Position and Lung Volume on the Center of Buoyancy of Competitive Swimmers

McLean, Scott P; Hinrichs, Richard N.

doi:10.1080/02701367.2000.10608896

Cited by 16 publications

(8 citation statements)

References 12 publications

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“…In previous studies, a swimmer’s horizontal posture was evaluated according to the positional relation between his/her CoB and CoM (McLean & Hinrichs [15, 17] Watanabe et al [18]). Therefore, it has generally been considered that shortening the CoB/CoM distance is necessary to achieve the ideal low-resistance posture.…”

Section: Discussionmentioning

confidence: 99%

“…The method of CoB measurement proposed by McLean & Hinrichs [17] was used for reference (see Fig 2). We installed a frame to secure the subject’s body on the poolside and attached Tension/Compression Load Cells (LUR-A-200NSA1, KYOWA ELECTRONIC INSTRUMENTS CO., LTD) on the hands and feet in a vertical direction to measure the force exerted on them in that direction.…”

Section: Methodsmentioning

confidence: 99%

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New evaluation index for the retainability of a swimmer’s horizontal posture

2017

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This study aims to investigate the effect of changes in buoyancy when a swimmer respires in a horizontal posture. We attempted to evaluate the levelness of swimmers’ streamline posture by simultaneously measuring the lung capacity and buoyancy under water. The buoyancy was measured based on the changes in the vertical loads of the upper and lower limbs on the subjects’ streamline posture under water. The horizontal x-axis as lung ventilation and the vertical y-axis as buoyancy forms a linear equation y = ax + b. The relation between hand (upper-limb) buoyancy and lung ventilation is defined as y = a1x + b1 and that between foot (lower-limb) buoyancy and lung ventilation as y = a2x + b2. Horizontal levelness was calculated as a ratio by dividing a2 by a1 using the inclination (a) values from these formulas for an underwater streamline posture. We defined this ratio as the breathing–balance (BB) ratio. Although the performance levels in the present study did not show any difference in the absolute quantity of air that humans can inhale in a streamline posture, the BB ratio was higher in a statistically significant manner in junior swimmers competing at international levels compared with the other groups of subjects (P < 0.001). This statistical difference in horizontal levelness, despite the absence of a noticeable difference in the absolute quantity of inhaled air, may be attributable to the way in which each person inhales and exhales air. Top-level junior swimmers that exhibited a high BB ratio might have inhaled in a way that would counteract the sinking of the lower limbs, for example, through abdominal respiration. When exhaling, on the other hand, they might have let out air gradually to mitigate the acceleration force involved in submerging the lower limbs.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

New evaluation index for the retainability of a swimmer’s horizontal posture

2017

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“…The stability of a human body in a horizontal, motionless floating position is determined by how the body is configured to form a certain posture and by the composition of the parts of the body. The state of breathing was found to affect the stability in a horizontal, motionless floating position [10,12]. Studies confirm that the legs in fact tend to sink.…”

Section: Does Our Body Float Motionless In Fresh Water?mentioning

confidence: 94%

How does buoyancy influence front‐crawl performance? Exploring the assumptions

Yanai¹,

Wilson

2008

Sports Technology

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“…Studies confirm that the legs in fact tend to sink. This is due to the buoyant force acting more cranial to the CM of the body (Figure 3), generating the moment around the CM that causes the legs to sink 7, 8–12. Some of these studies examined the sex differences in the body's stability and found that women tend to float more horizontally than men 10, 11, 13, due primarily to women having a greater amount of body adipose tissue stored around the hips and thighs, causing the CB to be located closer to the CM 11.…”

Section: Introductionmentioning

confidence: 99%

“…Some of these studies examined the sex differences in the body's stability and found that women tend to float more horizontally than men 10, 11, 13, due primarily to women having a greater amount of body adipose tissue stored around the hips and thighs, causing the CB to be located closer to the CM 11. The state of breathing was found to affect the stability in a horizontal, motionless floating position 10, 12. When air is inhaled, the lung volume increases and the CB shifts cranially to increase the leg‐sinking moment.…”

Section: Introductionmentioning

confidence: 99%