|Muscle strength is one of the key components in almost every sports performance. There are methods which can objectively quantify the actual status of athletes. A considerable amount of research papers has been published. They are focused on torque, position and time parameters with using isokinetic strength testing but often without any practical usage in real conditions. These studies often only describe and compare the sports disciplines or they try to evaluate concentric peak torque changes in time after selected interventions. On the other hand, too little attention is paid to eccentric strength and strength ratio between plantar and dorsiflexion of ankle joint. Strength ratio is well discussed especially for concentric flexion with concentric extension knee muscle strength within the same leg or combination of eccentric flexion and concentric extension. However, questions have been raised about using strength ratio in regards to predicting muscle regeneration or injury´s prevention as well. The objective of presented research is to purpose the effect of different pressure levels of compression calf sleeves used during uphill running on selected isokinetic parameters. The study was designed as a double-blind controlled laboratory study because of the elimination of researcher bias. Ten endurance-trained male athletes (age 24.8 ± 3.45 years; body weight 74.11 ± 8.63 kg; body height 1.81 ± 0.08 m; weekly running distance 43.0 ± 5.4 km; 10 km best time 38.0 ± 1.5 min) performed three 8 km treadmill runs at 75% VO2max with 6% incline while wearing compression calf sleeves (two types of graduated compression calf sleeves and one type inversely graduated compression). Maximal voluntary isokinetic concentric contraction and maximal voluntary isokinetic eccentric contraction of plantar flexors and dorsiflexors were recorded at 60 degrees/s, 120 degrees/s over 6 contractions with a Humac Norm dynamometer. No significant differences were found between graduated compression calf sleeves in peak torque of plantar flexors and dorsiflexors during isokinetic concentric and eccentric contraction (60 degrees/s, 120 degrees/s) in pre-test, 24 and 48 hours after the running protocol. Interestingly, analyses showed the significant difference in increasing peak torque of plantar flexors and dorsiflexors (60 degrees/s, 120 degrees/s) for inversely graduated compression calf sleeves during the isokinetic eccentric contraction. A difference between pre-test and 48 hours post run (p = 0.04123) was found. The obtained data indicate that inversely graduated compression calf sleeves (a higher pressure over the calf than over the ankle) may be much more practical during running especially in hilly mountainous terrain not only for running performance but also for reducing delayed onset muscle soreness.