Author(s): MANDADZHIEV, N., HRISCHEV, P., VASILEV, V., ANGELOVA, P., BOYADJIEV, N., GEORGIEVA, K., Institution: MEDICAL UNIVERSITY OF PLOVDIV, Country: BULGARIA, Abstract-ID: 1619

INTRODUCTION:
Maximal lactate accumulation rate or vLamax is a physiological parameter gaining popularity in sport science as a useful metric for evaluating the glycolytic muscle capacity of athletes. A popular method for testing the vLamax is by performing a maximal intensity test on a cycling ergometer with a duration of between 15 and 30 seconds. The objective of this study was to test whether incorporating a vLamax measurement in a standard isokinetic thigh strength assessment is practically viable and demonstrate any correlations between measured isokinetic strength parameters and glycolytic capacity.

METHODS:
The study included 11, recreationally active at the time of investigation, male participants (age: 24.91+/-4.08 years, height:179.2+/-6.19 cm, weight: 83.73+/-10.42 kg, body fat percentage: 14.49+/-3.01 %). Isokinetic strength assessment of knee flexion and extension was done using a HUMAC NORM isokinetic dynamometer (Computer Sports Medicine Inc., Stoughton, Massachusetts, USA). The contraction mode used was concentric at a set speed of 60 degrees/second. The test consisted of 5 maximal knee flexions and extensions with a total duration of 15 seconds and was performed on the dominant side of the subjects. Lactate was measured from earlobe blood samples, using a portable lactate meter Lactate Pro 2 (ARKRAY Inc., Kyoto, Japan). Sampling was done at rest before the test and immediately after the test in the course of five minutes. Statistical analysis was performed using JASP (Version 0.95.3).

RESULTS:
Mean vLamax values were 0.112+/-0.042 mmol/L/s. Mean lactate levels at rest were 1.600+/-0.349 mmol/L. Mean maximal lactate levels after the test were 2.945+/-0.592 mmol/L. Several isokinetic strength parameters were deemed relevant to vLamax: peak torque of knee extensors (265.1+/-43.59 N/m) and flexors (175.7+/-50.19 N/m), peak power of knee extensors (277.7+/-46.13 W) and flexors (145.9+/-29.20 W), time to peak torque for knee extensors (0.475+/-0.096 seconds) and flexors (0.504+/-0.150 seconds), total work done for the test (1411+/-273.2 J). Correlation analysis was performed between vLamax and those parameters. A weak positive relationship was observed between vLamax and knee extensor peak torque (r=0.257, p=.446), peak power (r=0.278, p=.408) and total work (r=0.252, p=.455), although not statistically significant. No relationships were found between vLamax and knee flexor peak torque and peak power, as well as the times to peak torque for both extensors and flexors.

CONCLUSION:
Although isokinetic strength testing elicits maximal effort, it doesn’t lead to meaningful vLamax results, mainly due to limiting movement to one muscle group. Moreover, weak correlations are observable between lactate accumulation and strength parameters, although not statistically significant due to the small sample size. We expect that further upscaling of the study protocol would result in significant correlations between vLamax and strength.