Age-related deficit in dynamic stability control after forward falls is affected by muscle strength and tendon stiffness

Exercise of mechanisms of dynamic stability improves the stability state after an unexpected gait perturbation in elderly

“…However, this increase in the knee extensor moment did not further increase the post-intervention recovery performance of the MT group. Earlier studies reported a contribution of 30-40 % of muscle strength to the capacity to recover balance with a single step after a forward fall (Wojcik et al 2001;Grabiner et al 2005;Karamanidis et al 2008). Therefore, we suggest that the increase of 13 % of the knee extensor strength in our study is probably too low to achieve an improvement in the stability performance.…”

“…The rapid generation of high moments is an important factor for successful balance recovery after perturbations (Pijnappels et al 2005;Hsiao-Wecksler and Robinovitch 2007;Karamanidis et al 2008;Mademli et al 2008), and therefore, we expected the MT group to achieve higher improvements in the dynamic Table 2 Mean values of the stability parameters (mean ± SD) in the three examined groups before (pre) and after (post) the intervention in the last step before the exchangeable element (time frame between touchdown left and touchdown of the right leg, baseline (unperturbed trials) Table 3 Mean values of the stability parameters (mean ± SD) in the three examined groups before (pre) and after (post) the intervention in the last step before the perturbation (time frame between touchdown left and touchdown of the right, disturbed leg, soft surface trial) (2013) 35:1905-1915stability in comparison to the ST group. The adequate generation of the hip moment seems to be a major contributor to successful balance recovery .…”

“…Reasons for the decreased ability to recover balance are the age-related reduction in muscle strength and tendon stiffness (Grabiner et al 2005; Karamanidis et al 2008), the delayed generation of propulsive ground reaction forces and joint torques (Robinovitch et al 2002;Pijnappels et al 2005;Tseng et al 2009), and the lower muscular contraction velocities (Hortobágyi et al 1995;Thelen et al 1997). If the postural system is unstable, stepping strategies seem to be less successful for the elderly due to reductions in step length and speed (Wojcik et al 2001;Karamanidis et al 2008;Bierbaum et al 2010). Furthermore, decreased recovery performance is attributed to deficits in the application of the mechanisms of dynamic stability .…”

A wide number of trials is required to achieve acceptable reliability for measurement patellar tendon elongation in vivo

“…An increasing stiffness, elastic modulus [4][5][6][7][8][9][10] and ultimate tensile strength [5] of tendons have been observed after interventions of mechanical loading, as well as a hypertrophy of the trained tissue [5,9,11]. Furthermore, it has been shown that the mechanical properties of tendons have a significant influence on running economy [12,13], sprint performance [28], and the dynamic stability control after sudden postural perturbations [14]. Inadequately adaptation of the patellar tendon is a frequent source of pain-related aborts of training [15] leading to jumper's knee [15][16][17] and other patellar tendinopathies.…”

Isokinetic Strength and Endurance in Proximal and Distal Muscles in Patients With Peripheral Artery Disease

“…1 As a consequence, most PAD patients present claudication symptoms, leading to impaired walking ability. 2,3 The aging process results in decreased muscle function, 4,5 which has been associated with an increased risk of falls, 6,7 leading to impairments in daily activities. 7,8 In PAD patients, aside from the effects of aging, lower-extremity strength deficits are associated with walking impairment, 9 reduced physical functioning, poor capacity for walking faster, and reduced stair-climbing ability.…”