Different strength declines in leg primary movers versus stabilizers across age—Implications for the risk of falls in older adults?

Abstract

This study investigated differences in the declines of isometric strength in hip abductors and adductors versus knee extensors across four different age groups (n = 31: 11.2 ± 1.0 y, n = 30: 23.1 ± 2.7 y, n = 27: 48.9 ± 4.4 y, and n = 33: 70.1 ± 4.2 y) with a total of 121 female subjects. As a starting point, we assumed that, during their daily activities, elderly people would use their leg stabilizers less frequently than their leg primary movers as compared to younger people. Given that muscle strength decreases in the course of the aging process, we hypothesized that larger strength declines in hip abductors and hip adductors as compared to knee extensors would be detected across age. Maximal isometric force for these muscle groups was assessed with a digital hand-held dynamometer. Measurements were taken at 75% of the thigh or shank length and expressed relative to body weight and lever arm length. Intratester reliability of the normalized maximal torques was estimated by using Cronbach’s alpha and calculated to be larger than 0.95. The obtained results indicate a clearly more pronounced strength decline in hip abductors and hip adductors across age than in the knee extensors. Therefore, a particular need for strength training of the lower extremity stabilizer muscles during the aging process is implied.

Balance Exercise Circuit for fall prevention in older adults: a randomized controlled crossover trial

“…This is because, during the aging process, it is natural for there to be a decrease in muscle strength, with strength declines being detected in the abductors, hip adductors, and knee extensors. Evidence shows that older adults use the primary motor muscles in their daily activities at a higher intensity than the leg stabilizers, which may perhaps lead to weak support during gait and in the bipedal position, with a particular need for strength training of lower limb muscles with emphasis on knee extensors and lower limb stabilizers[ 9 , 10 ]. In addition, strong evidence supports that specific exercise can reduce the risk and rate of falls in older adults[ 1 , 3 , 11 - 14 ].…”

Reliability and validity of an adapted hip abductor strength measure as a potential new fall risk assessment for older persons: a study protocol

“…Functional lower-extremity weakness has been shown important to enhance the risk of the transition from a non-faller into a faller [ 7 ]. Hip abductor muscle strength shows a more pronounced decline in older persons than hip extensor muscle strength of the leg [ 8 ]. The hip abductor muscle group particularly also is perceived to be important for older persons because of their significant role in maintaining mediolateral balance control [ 9 – 11 ] and their relation to lateral and posterolateral falls [ 12 ].…”

Impact of different bilateral knee extension strengths on lower extremity performance

“…[1,11,[23][24][25][26] Therefore, a decline in the muscle mass of both legs is considered a major factor for the development of muscle weakness in older adults and is obvious in regions, such as Japan, the United States, and Europe, where society is dramatically aging. [1,6,26,27] Heterogeneous reductions in both legs' muscle strengths in particular may be clinically relevant to determine the relationship between lower extremity motor performance and leg muscle strength. [7] The association between strength and performance has been estimated by both linear and non-linear models.…”

“…Walking and sit-to-stand progression are considered essential lower extremity motor functions in daily life [1][2][3][4][5] ; however, motor performance declines with aging [6][7][8] and is associated with daily dysfunction, [9][10][11][12] falls, [13] cognitive disorder, [14][15][16] decreasing quality of life, [17] hospitalization, [18,19] and mortality. [20][21][22] Previous studies have reported that weakness in both legs is an important risk factor for the inability to perform lower limb motor functions, such as sitting-to-standing movement and walking.…”

“…Previous studies have reported that weakness in both legs is an important risk factor for the inability to perform lower limb motor functions, such as sitting-to-standing movement and walking [1,11,23–26] . Therefore, a decline in the muscle mass of both legs is considered a major factor for the development of muscle weakness in older adults and is obvious in regions, such as Japan, the United States, and Europe, where society is dramatically aging [1,6,26,27] . Heterogeneous reductions in both legs’ muscle strengths in particular may be clinically relevant to determine the relationship between lower extremity motor performance and leg muscle strength [7] …”