Muscle Fiber Typology and Its Association With Start and Turn Performance in Elite Swimmers

Are there differences in anaerobic relative muscle power between upper and lower limbs in adolescent swimmers: A blinded study

Success in speed swimming depends on the efficiency of the anaerobic system for the production of cellular energy, especially during muscle power production. In the adolescent athletes much is unknown with regards to the relationships between relative power of upper and lower limbs with speed swimming performance. The aim the present study was to identify differences in relative muscle power of upper and lower limbs in adolescent swimmers and relate these to speed swimming performances. Sixty adolescents, of both sexes (50% female, 50% male, 30 swimmers and 30 controls), were recruited. The relative upper limb power (ULP[W/kg]) was assessed by a medicine ball test and the relative lower limbs power (LLP[W/kg]) by a jump test on a jumping platform. Lean mass of the upper and lower limbs was assessed by dual-energy X-ray absorptiometry (DXA) (g). Sport performance was assessed during national level competition (50-m swimming time [in seconds]). Biological maturation (BM) was indexed by years from attainment of peak height velocity. ULP(W/kg) was higher than LLP(W/kg) in both groups (p ​< ​0.05). Upper and lower limb lean mass (g) correlated significantly with ULP(W/kg) and LLP(W/kg) in both groups (p ​< ​0.05). ULP(W/kg) and LLP(W/kg) correlated with 50-m swimming performance (s), in both sexes (p ​< ​0.05). Advanced BM was associated with ULP(W/kg) and LLP(W/kg) in both groups (p ​< ​0.05), and with 50-m swimming performance (s) in both sexes (p ​< ​0.05). We concluded that ULP(W/kg) is higher than LLP (W/kg) in adolescent swimmers. Upper and lower limb lean mass and BM were both positively associated with increased ULP (W/kg) and LLP (W/kg).

Competition and Training Strategies for Developing World Class 200- and 400-m Individual Medley Swimmers

Swimming performance achieved in 50-m, 100-m and 200-m events in each swimming stroke can have an influence on the final performance in individual medley (IM) events. We attempted to quantify the relative contributions of performance in individual stroke events to top-10 world ranked IM competition performance. We examined competition results of top-10 world ranked IM swimmers (90 males and 90 females) between 2012 and 2018. A general linear model was developed to examine association between the 200-m and 400-mIM and predictor variables of competition performance in other 50-m, 100-m, and 200-m events. The main predictor variable for 200-mIM medalist status was having scored more than 900 FINA points in at least one 100-m event. Scoring more than 800 FINA points in at least two 200-mIM events, and more than 900 FINA points in at least one 100-m event, was important for success in the 400-mIM. Top-10 world ranked 200-mIM and 400-mIM swimmers require a world class standard in one or more individual stroke event(s).

The Relevance of Muscle Fiber Type to Physical Characteristics and Performance in Team-Sport Athletes

PURPOSE

The aim of this systematic review was to (1) determine the muscle fiber-type composition (or muscle fiber typology [MFT]) of team-sport athletes and (2) examine associations between MFT and the physical characteristics and performance tasks in team-sport athletes.

METHODS

Searches were conducted across numerous databases-PubMed, SPORTDiscus, MEDLINE, and Google Scholar-using consistent search terms. Studies were included if they examined the MFT of team-sport athletes. Included studies underwent critical appraisal using the McMasters University critical appraisal tool for quantitative research.

RESULTS

A total of 10 studies were included in the present review, wherein the MFT of athletes was measured from 5 different team sports (soccer, rugby union, rugby league, handball, and volleyball). There was large variability in the MFT of team-sport athletes both within (up to 27.5%) and between sports (24.0% relative difference). Male football players with a higher proportion of type II fibers had faster 10- and 30-m sprint times, achieved a greater total distance sprinting (distance at >6.67 m·s-1), and a greater peak 1-minute sprint distance.

CONCLUSIONS

MFT varies considerably between athletes both within and between different team sports. The results from some studies suggest that variation in MFT is associated with high-intensity running performance in a football match, as well as 10- and 30-m sprint times. Further experimental studies should focus on how determination of the MFT of team-sport athletes could be utilized to influence talent identification, team selection, and the individualization of training.

Association between the dry-land strength & power and the kick start kinetics in elite male and female swimmers

The aim of this research was to determine the association between dry-land exercises and the start kinetics in elite swimmers. Fourteen swimmers (eight males and six females) included in a national team took part in this study. A fixed smith-machine was used to measure the maximal full squat strength (Smax). The height of squat (SJ) and countermovement (CMJ) jumps were collected with a contact mat. The ground reaction force of the kick starts in the three-dimensional axis (Fz horizontal; Fy, vertical; Fx, lateral) was obtained by an instrumented force plate in the starting block. Overall, the Smax showed a high and significant association with Fz (r = 0.60) and Fy (r = 0.87). Moderate and significant associations were found between Fy and SJ (r = 0.51) and CMJ (r = 0.57). While Smax in males showed high association with Fy (r = 0.77), the Smax for females showed greater association with Fz (r = 0.84). As conclusion, the full back squat seems to be the dry-land exercise with higher association with the kick start kinetics. While in males the full squat defines better the vertical component, for females it defines the horizontal one.

The Muscle Typology of Elite and World-Class Swimmers

PURPOSE

To examine whether the muscle typology of elite and world-class swimmers could discriminate between their best distance event, swimming stroke style, or performance level.

METHODOLOGY

The muscle carnosine content of 43 male (860 [76] FINA [Fédération Internationale de Natation] points) and 30 female (881 [63] FINA points) swimmers was measured in the soleus and gastrocnemius by proton magnetic resonance spectroscopy and expressed as a carnosine aggregate Z score (CAZ score) to estimate muscle typology. A higher CAZ score is associated with a higher estimated proportion of type II fibers. Swimmers were categorized by their best stroke, distance category (sprinters, 50-100 m; middle distance, 200-400 m; or long distance, 800 m-open water), and performance level (world-class, world top 10, or elite and world top 100 swimmers outside of the world top 10).

RESULTS

There was no significant difference in the CAZ score of sprint- (-0.08 [0.55]), middle- (-0.17 [0.70]), or long-distance swimmers (-0.30 [0.75], P = .693). World-class sprint swimmers (all strokes included) had a significantly higher CAZ score (0.37 [0.70]) when compared to elite sprint swimmers (-0.25 [0.61], P = .024, d = 0.94). Breaststroke swimmers (0.69 [0.73]) had a significantly higher CAZ score compared to freestyle (-0.24 [0.54], P < .001, d = 1.46), backstroke (-0.16 [0.47], P = .006, d = 1.42), and butterfly swimmers (-0.39 [0.53], P < .001, d = 1.70). Furthermore, within the cohort of breaststroke swimmers, there was a significant positive correlation between FINA points and CAZ score (r = .728, P = .011); however, this association was not evident in other strokes.

CONCLUSION

While there was no clear association between muscle typology and event distance specialization, world-class sprint swimmers possess a greater estimated proportion of type II fibers compared to elite sprint swimmers, as well as breaststroke swimmers compared to freestyle, backstroke, and butterfly swimmers.