Background:Isokinetic dynamometer is currently regarded as the gold standard for evaluating muscle function, however, its application by coaches and athletes is still limited on
account of its high cost. Tests should be made with more affordable alternatives for evaluating muscle function in order to identify potential tools that would enable collecting robust information
about the strength produced by swimmers. Objective: To describe muscle strength in open water swimmers as estimated by different measuring instruments.
Methods:A total of 14 recreational swimmers who participate in open water competitions (mean age 36 ± 10.2 years, height 172.3 ± 7.8, total body mass 76.6 ± 11.9, body fat percentage
17.6 ± 6.0, fat weight 13.4 ± 4.8, lean weight 63.2 ± 11.0. Muscle function was assessed in the following devices: isokinetic dynamometer (Biodex, Lumex Inc., Ronkonkoma, NY), where participants
underwent 3000/s tests measuring average peak torque for a set of 30 repetitions of the elbow extension; The second test was handgrip strength using a hydraulic dynamometer (Jamar ®), with 3 attempts
with 30-second intervals between them. Highest value obtained was recorded for data analysis. The third device was a Xingu Sporting® sphygmomanometer which swimmers used during crawl stroke at full
speed for 15 seconds with an interval of two minutes in the following ways: front crawl full strokes and front crawl unilateral strokes. Description of variables was used for data analysis, followed
by Pearson correlation coefficient for detecting the magnitude of the relationship between the three strength measuring instruments used by swimmers. The accepted level of significance was ≤ 0.05.
Results:The isokinetic dynamometer indicated that the strength applied by swimmers in Newton/meter (N/m) was: right arm (bd) 38.64 ± 14.3; left arm (be) 36.48 ± 12.24. Handgrip
dynamometer readings in Kilos (kg) showed that the strenght produced was as follows: bd 41.08 ± 12.99 and be 40.18 ± 10.49. In the sphygmomanometer in a given swimming situation, the strength applied
in Kilos (Kg) was bd 10, 50 ± 3.70 and be 10.88 ± 4.33; in full stroke: 18.10 ± 4.33. Intertest correlation coefficient for the right arm indicated: isokinetic dynamometer/handgrip - r 0.647 (p =
0.05); isokinetic dynamometer/sphygmomanometer r 0.808 (p = 0.01); isokinetic dynamometer/full crawl swimming r 0.952 (p = 0.01); handgrip/sphygmomanometer r 0.577 (p = 0.05); handgrip/full swimming r
0.772 (p = 0.01); sphygmomanometer/full swimming r 0.812 (p = 0.01). For the left arm were identified: isokinetic dynamometer/ handgrip r 0.853 (p = 0.01); isokinetic dynamometer/sphygmomanometer r
0.909 (p = 0.01); isokinetic dynamometer/full crawl swimming r 0.902 (p = 0.01); handgrip/sphygmomanometer r 0.782 (p = 0.01); handgrip/full swimming r 0.856 (p = 0.01); sphygmomanometer/full swimming
r 0.958 (p = 0.01).
Conclusions: Results of the study sample indicated that the two low-cost instruments showed to be reliable for measuring the muscle strength of open water swimmers when compared to
the gold standard in the isokinetic evaluation.