RESUMO
Purpose: To explore the presence of intratendinous air in physically active males after different types of strenuous physical exercise. Materials and Methods: To detect foci (air bubbles) in the quadriceps femoris tendon (QFT) and the proximal and distal parts of the patellar tendon, ultrasound examination was performed under two conditions: (1) after high-intensity cycling on a cycle ergometer (metabolic); (2) after 200 drop jumps (exercise-induced muscle damage). Based on the results of these two interventions, the presence of air in the tendons after 100 drop jumps was examined further with frequently repeated ultrasound measurements. Results: Foci were detected in exercise-induced muscle damage. Twenty-three of Sixty investigated tendons (38.3%) were observed to contain hyperechoic foci after 100 drop jumps. QFT foci were present in 13/23 cases (56.5%). The location of foci in the QFT was mostly lateral and centro-lateral (76.9%). The foci disappeared completely between 40 and 180 min after completing 100 drop jumps. Conclusions: The presence of intratendinous air seems related to high-magnitude, high-force, high-strain exercise of the particular tendon areas. It might represent the stress response of tendons to overload condition.
RESUMO
The aim of this study was to assess changes in indirect markers of muscle damage and type I collagen degradation, as well as, patellar and Achilles tendon morphological differences during nine daily drop-jumps sessions with constant load alternated with rapid increases in load to test the hypothesis that frequent drop-jump training results in negative muscular and tendon adaptation. Young men (n = 9) performed daily drop jump workouts with progression every 3 days in terms of number of jumps, platform height and squat amplitude. Voluntary and electrically evoked knee extensor torque, muscle soreness, blood plasma creatine kinase (CK) activity and carboxyterminal cross-linked telopeptide (ICTP), patellar and Achilles tendon thickness and cross-sectional area (CSA) were assessed at different time points during the training period and again on days 1, 3, 10 and 17 after the training. The findings were as follows: (1) steady decline in maximal muscle strength with major recovery within 24 hours after the first six daily training sessions; (2) larger decline in electrically induced muscle torque and prolonged recovery during last three training sessions; (3) increase in patellar and Achilles tendons CSA without change in thickness towards the end of training period; (4) increase in jump height but not in muscle strength after whole training period. Our findings suggest that frequent drop-jump sessions with constant load alternated with rapid increases in load do not induce severe muscle damage or major changes in tendons, nonetheless, this type of loading is not advisable for muscle strength improvement. Key pointsFrequent drop jump training induces activation mode dependent muscle torque depression late in the training period.No significant changes in the thickness of patellar and Achilles tendons are observed during frequent training, while CSA increases towards the end of training period.Longitudinal effect for jump height but not for muscle strength is evident after the whole training period.
