Muscle size, strength, power, and echo intensity, but not specific tension, are affected by age in physically active adults

Article type: Research Article

Authors: Magrini, Mitchel A.^a | Colquhoun, Ryan J.^a | Barrera-Curiel, Alejandra^a | Thiele, Ryan M.^b | DeFreitas, Jason M.^a | Smith, Doug B.^a | Jenkins, Nathaniel D.M.^{a; *}

Affiliations: [a] Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater, OK, USA | [b] Department of Food, Nutrition, Dietetics and Health, Kansas State University, Manhattan, KS, USA

Correspondence: [*] Corresponding author: Nathaniel D.M. Jenkins, Applied Neuromuscular Physiology Laboratory, Oklahoma State University, 187 Colvin Recreation Center, Stillwater, OK 74074, USA. Tel.: +1 405 744 9315; E-mail: [email protected].

Abstract: OBJECTIVE: We examined the relationships among and differences between muscle size and strength, specific tension (MQST), echo intensity (MQEI), and functional performance in physically active younger and older women. METHODS: Measurements included maximal voluntary isometric knee extension contractions (MVICs), maximal velocity sit-to-stand (STS) movements, and muscle cross sectional area (mCSA), MQST, and MQEI of the rectus femoris (RF). RESULTS: There were no differences in MQST (p= 0.96) or physical activity levels (p= 0.29). MQST and MQEI were not related in the younger women, but were related in the older women (r= 0.50). MVIC was related to mCSA (r= 0.75) in the older women, but was not significantly related to MQST or MQEI in either age group. DISCUSSION: Physical activity may maintain MQST in aging. We suggest that studies examining changes in skeletal muscle with aging utilize both traditionally calculated muscle quality (specific tension) and ultrasound EI.

Keywords: Aging, muscle, sit-to-stand, functional ability, ultrasound

DOI: 10.3233/IES-172194

Journal: Isokinetics and Exercise Science, vol. 26, no. 2, pp. 95-103, 2018