We examined muscle function, muscle architecture, and tendon length bilaterally in persons who experience a functional deficit 2 years after an Achilles tendon rupture. Eleven persons were investigated on the injured compared with the uninjured side 47 ± 7 months (mean ± SD) after a tendon rupture. Heel‐rise data, plantar flexion strength, tendon resting angle 3D MRI‐determined tendon length and muscle cross‐sectional area, ultrasound‐determined fascicle length, and pennation angle were obtained. The heel‐rise test yielded reduced max height (32%), number of repetitions (54%), and work performed (61%), P < .001. Plantar flexion strength was impaired (P < .001) with the knee in extension (20%‐42%) and flexion (29%‐39%). Muscle cross‐sectional area was reduced for both the soleus (36%) and gastrocnemius muscles (46%; P < .001). Both the soleus tendon (55%) and the gastrocnemius tendon (14%) were longer (P < .001), and the fascicle length of the medial gastrocnemius was substantially reduced (18%; P < .001). The difference in heel‐rise height correlated to that of the gastrocnemius tendon elongation, r = .66, P < .05, but not soleus tendon elongation. These data show that a functional deficit after an Achilles tendon rupture is associated with an elongated soleus and gastrocnemius tendon along with a reduced soleus and gastrocnemius muscle cross‐sectional area and gastrocnemius fascicle length.

Advanced glycation end-products (AGEs) accumulate with aging and have been associated with tissue modifications and metabolic disease. Regular exercise has several health benefits, and the purpose of this study was to investigate the effect of regular long-term exercise and diet on skin autofluorescence (SAF) as a measure of glycation and on Achilles tendon structure. In connection with the 2017 European Masters Athletics Championships Stadia, high-level male athletes (n = 194) that had regularly trained for more than 10 years were recruited, in addition to untrained controls (n = 34). SAF was non-invasively determined using an AGE Reader. Achilles tendon thickness and vascular Doppler activity were measured by ultrasonography, and diet was assessed by a questionnaire. There was no significant difference in SAF between the athletes and controls. However, greater duration of exercise was independently associated with lower SAF. Diet also had an effect, with a more “Western” diet in youth being associated with increased SAF. Furthermore, our data demonstrated that greater Achilles tendon thickness was associated with aging and training. Together, our data indicate that long-term exercise may yield a modest reduction in glycation and substantially increase Achilles tendon size, which may protect against injury.

To evaluate interventions to promote physical activity, valid outcome measures are important. This study evaluated the validity and reliability of the ActivPAL3™ and the SENS motion® activity monitors with regard to the number of steps taken, walking, and sedentary behavior in hospitalized patients ( n = 36 ) (older medical patients (+65 years) ( n = 12 ), older patients (+65) with acute hip fracture ( n = 12 ), and patients (+18) who underwent acute high-risk abdominal surgery ( n = 12 )). Both monitors showed good (≥60%) percentage agreement with direct observation for standing and no. of steps (all gait speeds) and high agreement (≥80%) for lying. For walking, ActivPAL3™ showed moderate percentage agreement, whereas SENS motion® reached high percentage agreement. The relative reliability was moderate for sedentary behavior for both monitors. The ActivPAL3™ showed poor (walking) to moderate (steps) reliability for walking and steps, whereas SENS motion® showed moderate reliability for both activities. For slow walkers, the relative reliability was moderate for SENS motion® and poor for ActivPAL3™. This trial is registered with the ClinicalTrials.gov identifier NCT04120740.