Author(s): GONJO, T., LJØDAL, I., OLSTAD, B.H., Institution: HERIOT-WATT UNIVERSITY, Country: UNITED KINGDOM, Abstract-ID: 2066

INTRODUCTION:
Load-velocity profiling has been used to estimate the maximum swimming velocity (V0) and maximum load the swimmer can withstand (L0). Theoretically, L0 should be closely related to the fully tethered swimming force (Gonjo et al., 2021), which is an indicator of the ability to generate the propulsive force. However, this assumption has never been tested. Therefore, the aim of the present study was to investigate the relationship between L0 and the fully tethered swimming force.
METHODS:
Thirteen male front crawl swimmers (19.14±2.46 years old, 1.838 ±0.072 m in height, 77.96±9.59 kg in body mass, and 652.31±117.66 World Aquatics point) performed a set of sprint semi-tethered swimming protocol consisting of three 25 m trials with three external loads, as well as three 10-second fully tethered swimming trials, in front crawl. Both semi-tethered swimming and fully tethered swimming sets were conducted with 1080 Sprint (1080 Motion, Lidingö, Sweden). The resistance load was set to 30 kg for fully tethered swimming trials. As this load was much higher than the typical estimated maximum load (about 22 kg) in front crawl swimming (Gonjo et al., 2021), this setting was deemed appropriate for the fully tethered swimming condition. In the fully tethered swimming trials, the first 2-3 seconds contained slight forward movement, presumably due to the large momentum from push-off. Therefore, this initial phase was excluded from the analysis. After trimming the data, the mean force value (FT) of the three fully tethered swimming outcomes was used for further analysis. L0 was estimated using the load-velocity profiling method, as described in Gonjo et al. (2021). The normality of data was checked using the Shapiro-Wilk test and confirmed for both L0 and FT. Therefore, the person’s correlation coefficient was used to assess the relationship between the two variables with alpha = 0.05.
RESULTS:
There was a significant correlation between L0 and FT (r=0.727, p=0.005). The inter-participant mean of FT was 155.77±27.49 N. When normalising this variable with the body mass, the inter-participant mean value was 1.99±0.19 N/kg, which was close to male competitive swimmers’ data presented in a previous study which reported FT of 133.2±16.8 N with 70.4±6.3 kg body mass (Loturco et al., 2016).
CONCLUSION:
In conclusion, L0 and FT are strongly related, which suggests that L0 is an indicator of a swimmer’s ability to generate the propulsive force.

REFERENCES:
Gonjo T, Njøs N, Eriksrud O and Olstad BH (2021) The Relationship Between Selected Load-Velocity Profile Parameters and 50 m Front Crawl Swimming Performance. Front. Physiol. 12:625411. doi: 10.3389/fphys.2021.625411
Loturco I, Barbosa AC, Nocentini RK, Pereira LA, Kobal R, Kitamura K, Abad CC, Figueiredo P, Nakamura FY. A Correlational Analysis of Tethered Swimming, Swim Sprint Performance and Dry-land Power Assessments. Int J Sports Med. 2016 Mar;37(3):211-8. doi: 10.1055/s-0035-1559694. Epub 2015 Dec 15. PMID: 26669251.