Perceived Quantity of Physical Activity as a Reflective Measure in Muscle and Bone Strength

Abstract

Perception plays a powerful role in shaping health outcomes. An active lifestyle, provides mechanical load needed to strengthen and maintain both muscle and bone health. Many recommendations on the quantity of physical activity needed for health benefits exist however it is unclear if individuals perception of their activity habits relates to muscle and bone strength benefits. PURPOSE: To determine if those who perceived that they get the right amount or more than needed amount of exercise, have greater muscle and bone strength. METHODS: 79 participants, 41 females and 38 males (age (yrs) 29.2 + 10.8, height (cm) 166.5 + 9.2, body fat % 24.6 + 9.3) performed a relative grip strength (RGS) test using a hand grip dynamometer, 1 repetition maximum leg extension test (1RM), and a vertical jump test using a Vertec (PP). Bone Strength Index (compression) (BSIc) and polar Strength-Strain Index (SSIp) were measured using peripheral Quantitative Computed Tomography (pQCT). A questionnaire stated “Do you feel you get too much exercise, too little exercise, or about the right amount of exercise?” Welch’s t-tests detected differences in muscle function and bone strength based on perception of exercise quantity (Above and Below). RESULTS: 41 participants perceived they got the “right amount of exercise or above” (Above) and 29 participants reported that they got below the right amount of exercise (Below). Perception of the Above group resulted in greater muscle function tests compared to the Below group (Average PP: 11.5% (p=0.004), RGS: 5.7% (p=0.004). “Right amount of exercise or above” resulted in greater bone strength (SSIp) at both the radius (11.7% (p=0.055) and tibia (13.3% p=0.02). CONCLUSIONS: Participants’ perception on quantity of exercise reflected their bone and muscle strength. Those who perceived that they get the appropriate or a higher amount of exercise had greater bone and muscle strength values compared to participants’ who perceived they exercised less. Perception of getting the “right amount of exercise or above” compared to “below right amount of exercise” was a good indicator of greater bone and muscle strength.