Impact of EMS and Compression Clothing on Muscle Strength and Activity

To evaluate how wearable technology can enhance physical performance, researchers at Dankook University conducted a study on the effects of EMS (Electrical Muscle Stimulation) combined with compression clothing. The goal: to understand how this combination influences muscle strength, activity, and fatigue in the elbow and knee joints.

Methodology:

The study involved ten healthy male adults between the ages of 20 and 30. Each participant completed three separate trials: one without any special clothing (control), one wearing only compression garments, and one wearing compression garments integrated with EMS. After each trial, the participants’ isokinetic muscle strength and muscle activity were measured at two angular velocities: 60°/sec (targeting maximum strength) and 180°/sec (targeting muscular endurance.

Muscle activity was tracked using surface electromyography (EMG) in key muscle groups; specifically, the biceps brachii, quadriceps femoris, and biceps femoris, while strength and power output were recorded using the Cybex HUMAC NORM system. Fatigue was measured via fatigue index, offering insights into how quickly muscles tired under each condition.

EMS Combined with Compression Outperforms in Every Category

Across all metrics, the EMS + compression clothing condition consistently led to the most pronounced improvements. From muscle activation to power output and endurance, this combination outperformed both the control and compression-only conditions.

Isokinetic Muscle Strength: Measurable Gains

When evaluating maximum torque during elbow flexion and extension at 60°/sec, the EMS + compression group achieved significantly higher values than the other two groups. Elbow flexors, for instance, peaked at 74.70 Nm/kg in the EMS + compression condition, over 10 Nm/kg higher than the control. Similar trends were observed in the knee joint, where peak torque for knee flexors reached 165 Nm/kg with EMS + compression, compared to 141 Nm/kg in the control group.

At 180°/sec, a speed designed to evaluate endurance and sustained output, EMS + compression clothing again came out on top. Average power and total work were highest in this group for both elbow and knee joints, indicating not just stronger but longer-lasting performance. For example, average power in the elbow flexors reached 81.50 W/kg with EMS + compression, compared to just 61.30 W/kg in the control condition.

Similar trends are observed when conducting tests on the knee joint area. Compression & EMS + compression clothing showed higher results in maximum strength and flexion and extension, there were no significant differences in knee joint strength was higher in the compression and EMS combines groups than the control group

Muscle Activity (EMG): Stronger Signals, Greater Recruitment

Muscle activity was measured via EMG in the same key muscle groups. EMS combined with compression clothing consistently produced the highest muscle activation across all measured regions. In the elbow, the biceps brachii reached an average of 399.22 µV with EMS + compression, compared to 308.51 µV in the control group. The quadriceps femoris showed a similar increase, peaking at 695.56 µV, nearly 90 µV higher than the control. These elevated values reflect stronger neuromuscular signals, increased muscle fiber recruitment, and greater overall activation, confirming that the EMS-enhanced garments are not merely supportive but actively performance-enhancing.

Fatigue: A Tradeoff Worth Considering

At the slower angular velocity (60°/sec), fatigue index readings revealed an expected side effect of higher performance: greater fatigue. In elbow extensors, the EMS + compression group registered a fatigue index of 14.3, compared to just 8.2 in the control. However, in other muscle groups such as the flexors, EMS + compression actually reduced fatigue, suggesting improved muscular efficiency in those areas.

Power and Total Work: Dominance at High Speed

At the higher testing speed of 180°/sec, which simulates more dynamic athletic movement, the EMS + compression group again showed clear superiority. For instance, total work done by the knee extensors reached 2,752 Nm/kg, significantly higher than both the compression-only (2,284 Nm/kg) and control (1,961 Nm/kg) conditions. These findings confirm that the addition of EMS doesn’t just offer peak performance but also sustained output under high-load conditions.

Statistical Significance & Implications

The study’s findings were backed by repeated measures ANOVA, confirming statistically significant improvements in multiple categories for the EMS + compression group. These included muscle activity, average power, and peak torque, particularly in the flexors and extensors of both elbow and knee joints.

While the higher fatigue index in certain areas reflects the increased demands placed on the body, the tradeoff is a clear performance edge; valuable for athletes, physical therapists, and anyone seeking measurable gains in strength and endurance.

This study offers compelling evidence that EMS-enhanced compression wear isn’t just hype; it’s a validated approach to improving muscle activation, increasing power, and enhancing endurance. Whether you're designing products for high-performance athletes or therapeutic use, integrating EMS into compression garments represents a meaningful leap forward in wearable sports science.