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Purpose: Recent evidence indicates that low-load blood flow restriction (LL-BFR) training elicits an anabolic response in tendinous tissue. The purpose of the present study was to investigate the hypertrophic pattern induced in the Achilles tendon by LL-BFR, in comparison with the regional hypertrophy typically observed with conventional high-load (HL) resistance training., Methods: N = 40 male participants were randomly and concealed allocated to one of two groups: LL-BFR training (20-35% one-repetition maximum/1RM) or HL training (70-85% 1RM). The training was completed three times per week for a total of 14 weeks. Before and after the training period, Achilles tendon morphology was assessed using magnetic resonance imaging along the entire tendon length. Additionally, dynamic strength measures of the plantar flexors were evaluated., Results: In line with previous findings, dynamic plantar flexion strength was improved to a comparable extent in both groups (LL-BFR: 43.6%; HL: 43.5%). The results also confirmed significant increases in Achilles tendon cross-sectional area with LL-BFR (+5.2%). Moreover, they revealed that the hypertrophic pattern obtained with LL-BFR was similar to regional changes seen with conventional HL training., Conclusion: The present findings point towards the notion that despite the low loads being applied, LL-BFR training induces Achilles tendon hypertrophy by potentiating anabolic responses in the same regions as with conventional high-load training. Future studies are needed to (i) focus on the potential mechanisms underlying these tendon morphology changes and (ii) apply and evaluate LL-BFR training in clinical populations to validate these results in rehabilitative settings., (© 2023 The Authors. Scandinavian Journal of Medicine & Science In Sports published by John Wiley & Sons Ltd.)

The purpose of this study was to investigate the effect of specific collagen peptides (SCP) combined with resistance training (RT) on changes in tendinous and muscular properties. In a randomized, placebo-controlled study, 40 healthy male volunteers (age: 26.3 ± 4.0 years) completed a 14 weeks high-load resistance training program. One group received a daily dosage of 5g SCP while the other group received 5g of a placebo (PLA) supplement. Changes in Achilles tendon cross-sectional area (CSA), tendon stiffness, muscular strength, and thickness of the plantar flexors were measured. The SCP supplementation led to a significantly (p = 0.002) greater increase in tendon CSA (+11.0%) compared with the PLA group (+4.7%). Moreover, the statistical analysis revealed a significantly (p = 0.014) greater increase in muscle thickness in the SCP group (+7.3%) compared with the PLA group (+2.7%). Finally, tendon stiffness and muscle strength increased in both groups, with no statistical difference between the groups. In conclusion, the current study shows that the supplementation of specific collagen peptides combined with RT is associated with a greater hypertrophy in tendinous and muscular structures than RT alone in young physically active men. These effects might play a role in reducing tendon stress (i.e., deposition of collagen in load-bearing structures) during daily activities., (© 2022 The Authors. Scandinavian Journal of Medicine & Science In Sports published by John Wiley & Sons Ltd.)

Explosive strength and balance training are commonly applied to enhance explosive strength and balance performance. Even though both training methods are frequently implemented, ordering effects have largely been neglected. Therefore, the present study aimed to investigate ordering effects of balance and explosive strength training on explosive strength and balance performance as well as changes in short-interval intracortical inhibition (SICI). Two groups of subjects either participated in 4 weeks of balance training followed by 4 weeks of explosive strength training (BT-ET) or vice versa (ET-BT). Before, after 4 and 8 weeks, balance performance, as well as explosive strength, was tested. Additionally, SICI was tested during rest as well as during balance perturbations and explosive contractions. The results show a training specific increase in performance with an increase in balance control followed by an increase in explosive strength in the BT-ET, while the ET-BT increased its balance and explosive strength in the opposite order. There were no significant ordering effects. Both groups showed a significant decrease in SICI during the explosive contractions after the eight weeks of training. When SICI was tested during the balance perturbations, SICI initially increased after the first 4 weeks of training but returned to baseline until the end of the eight weeks. It is suggested that the decrease in SICI with prolonged training might show a disengagement of the motor cortex during the balance task. During the explosive contractions, the low SICI levels are beneficial to provide the necessary level of excitatory cortical drive., (© 2021 The Authors. Scandinavian Journal of Medicine & Science In Sports published by John Wiley & Sons Ltd.)

Even though the take-off in ski jumping is decisive, athletes only have a very limited number of training trials on the actual ski jump to practice under real ski jump conditions. Hence, various imitation jumps aiming to mimic the hill jump are performed during daily training. These imitation jumps should therefore mimic the kinematic pattern of hill jumps appropriately. This study aimed to identify imitation jumps that resemble hill jumps regarding four performance-related biomechanical criteria: maximal vertical take-off velocity, maximal knee extension velocity, maximal forward-directed angular momentum and anterior shift of the center of mass. Therefore, a three-dimensional analysis of the take-off during six different modalities of imitation jumps as well as hill jumps for validation was carried out in nine professional ski jumpers. Imitation jumps from a rolling platform show better agreement than stationary jumps and three out of the four parameters were best resembled via an imitation jump that included ski jumping boots. Thus, non-hill take-off training should be performed with complex imitation jumps to mimic the actual ski jump. Except for the vertical take-off velocity, we could identify one imitation jump type that is not statistically different to the hill. Consequently, the individual deficiencies of the athletes can be addressed and specifically trained using the appropriate imitation jump. These information about the similarity between imitation jumps and real hill jumps are highly relevant for trainers and athletes in order to effectively design their training programs., (© 2020 The Authors. Scandinavian Journal of Medicine & Science In Sports published by John Wiley & Sons Ltd.)

This study examined the effect of drop height on neuromechanical control of the plantarflexors in drop jumps (DJs) before and during ground contact (GC). The effect of anticipation on muscle mechanical configurations was investigated in 22 subjects in three conditions (20, 30, and 40 cm): (i) known, (ii) unknown, or (iii) cheat falling heights (announced 40 cm, but actual drop height was 20 cm). Electromyographic (EMG) activity of the m. gastrocnemius medialis (GM) and other shank muscles was recorded and analyzed before GC and during GC separately for the short-, medium-, and long-latency responses (SLR, MLR, and LLR). Changes in GM fascicle length (L M ) were determined via B-mode ultrasound, and muscle-tendon unit length (L MTU ) was estimated. Peak force (P < .001), rate of force development (RFD) (P = .001) and GM EMG activity prior to (P = .003) and during GC (P = .007) was reduced in the unknown compared with the known conditions (P < .05). The amount of shortening in L MTU during GC in unknown and cheat was less compared with the known conditions (P = .005; P = .049). Changes in L MTU lengthening negatively correlated with changes in GM activity around SLR and MLR (P = .006; P = .02) in known and unknown conditions. Taken together, it seems that the central nervous system applies a protective strategy in the unknown condition by reducing muscle activity to result in a lower muscular stiffness and increased tendinous lengthening prior to and during GC. This might be a mechanism to absorb greater elastic energy in the tendon and reduce the magnitude and rate of muscle lengthening and subsequent stretch-induced muscle damage., (© 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)