Trunk Strength Characteristics of Elite Alpine Skiers - a Comparison with Physically Active Controls

We know a lot about little and little about a lot: A contextualized scoping review on injury prevention in alpine ski racing

BACKGROUND

Our goal was to summarize and contextualize the available literature on alpine ski racing injury epidemiology, injury etiology, injury prevention measures, injury prevention context, and implementation issues.

MATERIALS AND METHODS

We searched four electronic databases using predetermined search terms. We included original studies that assessed injury, injury risk factors, and injury mechanisms, and assessed and reported the effect of an injury prevention measure in alpine ski racing. Two authors independently conducted title-abstract screening, and one performed the full-text review. For data synthesis and categorization, we used the Translating Research into the Injury Prevention Practice framework and a modified and adapted version of the Haddon matrix.

RESULTS

Of the 157 included studies, most corresponded to injury epidemiology and etiology, whereas few studies encompassed injury prevention measure development, implementation and evaluation. Preventive interventions targeting equipment, rules and regulations, course design and snow preparation were the most prevalent in the literature. Furthermore, various contextual factors in the current literature have been found, including gender, competition level, countries and federations, and time periods within a season.

CONCLUSIONS

We provided an in-depth and comprehensive overview of the current state-of-the-art in the alpine ski racing context. We know a lot about little and little about a lot across all the areas associated with injury prevention in such context. The limitations in the literature yield a road map for designing future injury prevention studies to address the key gaps identified. A more comprehensive context-driven approach throughout all stages of injury prevention would benefit the ultimate implementation of effective preventive strategies.

The effect of gender, age and sports specialisation on isometric trunk strength in Greek high level young athletes

Aim of the study was to compare the isometric strength of flexors and extensors trunk muscles between male and female elite adolescent athletes of different age and training experience. Absolute and relative trunk muscle isometric peak extension (PTE) and flexion (PTF) torque, as well as flexion/extension (F/E) ratio were evaluated in 388 elite adolescent athletes 188 males (Age: 15.4±1.8 years, Body height: 175.5±11.2 cm, Body mass: 68.8±14.5 kg, BMI: 22.1±0.3 kg/m2) and 207 females (Age: 15.1±1.6 years, Body height: 166.8±7.8 cm, Body mass: 60.8±8.4 kg and BMI: 21.8±0.4 kg/m2). Participants were assigned into seven different groups according to their sport specialisation (oars-paddle, swimming, contact-combat, team, racket, winter and mixed other sports). Significant effect of age (η2: 0.077-0.112, p < 0.05), gender (η2: 0.020-0.077; p < 0.05) and sport category factors (η2: 0.057-0.154. p < 0.005) for absolute/relative PTE, PTF and F/E ratio was found. The highest values were observed in contact-combat and the lowest in mixed other sports groups. F/E ratio significantly differs between the age groups, especially in female athletes. The present data suggest that TMSs and F/E ratio are highly affected by age, gender and sports specialisation in high level trained adolescents.

The interactions between agonist-to-antagonist muscle strength performance and plantar pressure distribution, foot contact area, and impulse in novice ballet dancers

BACKGROUND

Hip, trunk, knee, and ankle/foot muscles may lead to increased variability in the components of balance and plantar pressure distribution (PPD) analysis. However, the role of these muscle groups in the PPD of different ballet techniques in novice ballet dancers has not previously been studied.

OBJECTIVE

Our objective was to examine whether balance and PPD vary among five different ballet techniques and correlate with the agonist-to-antagonist strength performance of trunk, knee, hip, and ankle muscles in adolescent ballet dancers.

METHODS

The anthropometric parameters, muscle strength performance, balance, and PPD of sixty healthy female ballet dancers (age: 14.36 ± 2.18 y) were measured at 48-h intervals.

RESULTS

The forefoot's PPD was significantly greater than the midfoot and rearfoot for all techniques (p= 0.000). The percent plantar load of forefoot during développé à la seconde (side, front, back), passé, and penché was greater than midfoot (166.56%, 161.51%, 168.11%, 165.14%, 174.04%) and rearfoot (47.75%, 32.84%, 43.83%, 48.73%, 49.66) for all techniques, respectively. The forefoot's PPD, impulse, and contact area during all techniques were significantly correlated with the trunk muscle strength ratio (p< 0.05).

CONCLUSION

Ballet dancers with higher trunk muscle strength imbalance showed a greater percentage difference in pressure load between the left and right foot in the anterior and posterior directions, poor balance, aggravated trunk imbalance, increased PPD, contact area, and impulse in the forefoot during each technique.

Hand Grip Strength vs. Locomotor Efficiency in Sitting Volleyball Players

The objective of this paper was to determine the relationship between hand grip strength and movement time (locomotor efficiency in a seated position using the upper and lower extremities) in sitting volleyball players. In addition, a comparison was made between the velocity curves for forward and backward locomotion. Nine male members of the sitting volleyball team participated in the study. Hydraulic and spring manual dynamometers were used to measure hand grip strength. Movement times were registered for distances of 1, 2, 3, 4, 5, 6 and 10-m with the use of the Smart Speed System photocells. Significant relationships between hand grip strength of the left (r_s=-0.78) and right (r_s=-0.73) hands and the forward movement time over a distance of 1-m were found. Hand grip strength had no significant relationship with either forward movement times at other distances or backward movement times. Results suggest that hand strength is linked to locomotor efficiency of sitting volleyball players. High hand grip strength makes the start easier by pushing away from the ground with the upper limbs.

Effect of Skiing on Physical Performance, Pain, and Quality of Life Based on Gender

Context: Identifying gender-specific differentiation in each sport type is significant. In this way, sport- and gender-specific gains can be predicted. Therefore, this study aimed to examine the effects of skiing on physical performance, pain, quality of life, and gender-based differentiation. Design: Crossover trial. Methods: Sixty-eight volunteers, between 18 and 25 years of age, with no history of severe trauma in the spine and extremities, participated in our study. The skiers group consisted of licensed athletes (17 males and 17 females) who did active skiing for at least the past 2 years, the control group consisted of nonathletic and age-matched participants with no skiing experience (17 males and 17 females). Step test, vertical jump test, Flamingo balance test, hand-grip strength, and back-leg-chest strength measurements were performed to evaluate physical performance. Visual Analog Scale, McGill Pain Questionnaire, and Oswestry Low Back Pain Disability Questionnaire were used to evaluate pain experience. Quality of life was evaluated with Short Form-36 (SF-36). Results: Compared to the sedentary controls, VAS-activity and Oswestry Disability Index scores were lower; and aerobic performance, balance, hand-grip strength, back-leg-chest strength, and quality of life (SF-36-general health, SF-36-vitality, SF-36-mental health, and SF-total score) were higher in skiers. Skiing was found to be effective in eliminating gender-based differentiation of the variables of hand-grip strength, pain, and quality of life; however, back-leg-chest strength and anaerobic performance variables were found to be ineffective in eliminating gender differentiation. Conclusions: Skiing allows that the individual increases physical performance and quality of life. It can also minimize gender-based differentiation of certain variables, such as muscular force, pain, and quality of life.

Physical fitness is associated with better technical performance in adolescent alpine ski racers after controlling for practice time: A retrospective regression analysis

In an effort to evaluate the mechanisms underpinning performance in alpine ski racing, researchers have focused on the predictive validity of measures derived from fitness assessments. However, a limitation of this literature is the absence of practice time, since prolonged training may naturally develop specific fitness capacities, making some tests of physical ability less predictive of performance. We examine the relationship between fitness tests, practice, and performance using linear regressions with fitness test data, practice history data, and performance results from adolescent alpine ski racers attending professional development academies in the United States (N = 82). Only aerobic capacity (i.e. 20 m shuttle run) was significantly associated with more practice time. After controlling for practice hours, 5.5-6.5% of variance in ski performance was significantly explained by assessments of lower body power (i.e. standing long jump, triple jump), anaerobic capacity (i.e. 60 s box jump), and upper body strength/endurance (i.e. push-ups). Findings highlight the important role of anaerobic power on alpine ski racing performance, which may be developed outside of regular practice, possibly through weight training or physical maturation. The small variance explained by physical/physiological measures suggests that superior ski performance is likely a product of various skills and characteristics (e.g. technical, tactical, perceptual-cognitive, psychosocial).