Patterns of anterior and posterior muscle chain interactions during high performance long-hang elements in gymnastics

Validity of Gymnastics-Specific Assessment of Neuromuscular Function of Shoulder Flexor and Extensor Muscles to Predict Performance in Gymnastics Skills

ABSTRACT

Milosis, DC. Validity of gymnastics-specific assessment of neuromuscular function of shoulder flexor and extensor muscles to predict performance in gymnastics skills. J Strength Cond Res 37(3): 652-660, 2023-This study examined the relationships between gymnastics-specific laboratory measurements of neuromuscular function of the shoulder flexor and extensor muscles and performance in specific gymnastics skills. Fifteen highly competitive male gymnasts and 18 male students (age 20.41 ± 2.51 years, body mass 69.7 ± 7.07 kg; mean ± SD ) participated voluntarily. The electromyogram (EMG) was used to assess muscle activation of 3 flexor and 3 extensor shoulder muscles during isometric (45, 90, and 135°) and isokinetic (concentric and eccentric 60, 180, and 300°/s) flexion-extension of the shoulder. Peak torque (PT), neuromuscular efficiency (NME: torque to EMG ratio), and antagonist coactivation index (CI) were evaluated. Furthermore, performance in specific gymnastics skills was evaluated. The results supported the ecological validity of the measurements. Specifically, significant correlations emerged between the shoulders' neuromuscular function parameters and the performance in the gymnastics skills (PT: r = 0.798, p < 0.001, NME: r = 0.576, p < 0.001, CI: r = -0.351, p < 0.05). In addition, according to the results of the regression analysis, neuromuscular function of the shoulder flexor and extensor muscles predicted gymnastics performance. Specifically, the model that was produced significantly predicted the dependent variable (performance in specific gymnastics skills) in all steps and explained a total variance of 64.4% ( p < 0.001). Based on beta coefficients, PT had the higher contribution to the prediction of performance. The insight gained on these relationships could help coaches to plan the training of their gymnasts and to monitor the longitudinal changes in neuromuscular function of shoulder muscles induced by training more effectively.

Current issues and future directions in gymnastics research: biomechanics, motor control and coaching interface

The sport of gymnastics is undergoing a global examination of its culture and the relationship between the gymnast, coach and environment is a central focus. The aim of this review is to explore biomechanics and motor control research in skill development and technique selection in artistic gymnastics with a focus on the underlying concepts and scientific principles that allow performance enhancement, skill development and injury risk reduction. The current review examines peer reviewed papers from 2000 onwards, with a focus on contemporary approaches in the field of gymnastics research, and highlights several key directions for future gymnastics research. Based on our review and the integration of the models of Newell (1986) and Irwin et al. (2005), we recommend that future gymnastics research should embrace at the very least a multidisciplinary approach and aim for an interdisciplinary paradigm.

Longitudinal sequencing in intramuscular coordination: A new hypothesis of dynamic functions in the human rectus femoris muscle

The punctum fixum-punctum mobile model has been introduced in previous publications. It describes general principles of intersegmental neuromuscular succession patterns to most efficiently generate specific movement intentions. The general hypothesis of this study is that these principles—if they really do indicate a fundamental basis for efficient movement generation—should also be found in intramuscular coordination and should be indicated by “longitudinal sequencing” between fibers according to the principles of the punctum fixum-punctum mobile model. Based on this general hypothesis an operationalized model was developed for the rectus femoris muscle (RF), to exemplarily scrutinize this hypothesis for the RF. Electromyography was performed for 14 healthy male participants by using two intramuscular fine wire electrodes in the RF (placed proximal and distal), three surface electrodes over the RF (placed proximal, middle, and distal), and two surface electrodes over the antagonists (m. biceps femoris and m. semitendinosus). Three movement tasks were measured: kicking movements; deceleration after sprints; and passively induced backward accelerations of the leg. The results suggest that proximal fibers can be activated independently from distal fibers within the RF. Further, it was shown that the hypothesized function of “intramuscular longitudinal sequencing” does exist during dynamic movements. According to the punctum fixum-punctum mobile model, the activation succession between fibers changes direction (from proximal to distal or inversely) depending on the intentional context. Thus, the results seem to support the general hypothesis for the RF and could be principally in line with the operationalized “inter-fiber to tendon interaction model”.

The punctum fixum-punctum mobile model: a neuromuscular principle for efficient movement generation?

According to the “punctum fixum–punctum mobile model” that was introduced in prior studies, for generation of the most effective intentional acceleration of a body part the intersegmental neuromuscular onset succession has to spread successively from the rotation axis (punctum fixum) toward the body part that shall be accelerated (punctum mobile). The aim of the present study was to investigate whether this principle is, indeed, fundamental for any kind of efficient rotational accelerations in general, independent of the kind of movements, type of rotational axis, the current body position, or movement direction. Neuromuscular onset succession was captured by surface electromyography of relevant muscles of the anterior and posterior muscle chain in 16 high-level gymnasts during intentional accelerating movement phases while performing 18 different gymnastics elements (in various body positions to forward and backward, performed on high bar, parallel bars, rings and trampoline), as well as during non-sport specific pivot movements around the longitudinal axis. The succession patterns to generate the acceleration phases during these movements were described and statistically evaluated based on the onset time difference between the muscles of the corresponding muscle chain. In all the analyzed movement phases, the results clearly support the hypothesized succession pattern from punctum fixum to punctum mobile. This principle was further underlined by the finding that the succession patterns do change their direction running through the body when the rotational axis (punctum fixum) has been changed (e.g., high bar or rings [hands] vs. floor or trampoline [feet]). The findings improve our understanding of intersegmental neuromuscular coordination patterns to generate intentional movements most efficiently. This could help to develop more specific methods to facilitate such patterns in particular contexts, thus allowing for shorter motor learning procedures of context-specific key movement sequences in different disciplines of sports, as well as during non-sport specific movements.