Acute effects of combined static stretching and electrical stimulation on joint range of motion and passive stiffness

Abstract

This study aimed to determine the acute effects of combined static stretching (SS) and electrical stimulation (ES) on joint range of motion (ROM) and passive muscle and tendon properties. Sixteen healthy men participated in two randomly ordered experimental trials, which comprised a combination of SS and ES (SS + ES), and SS alone. In the SS + ES trial, participants performed 5 minutes of calf stretching while receiving ES of the gastrocnemius medialis, whereas in the SS trial the participants performed calf stretching only. Maximal dorsiflexion angle, passive torque, and displacement of the muscle-tendon junction were measured before and after intervention. The stiffness of the muscle and muscle-tendon unit was calculated.Compared with the pre-intervention values, there were significant increases in ankle ROM and passive torque at maximal dorsiflexion angle after both interventions. In addition, the passive torque at the submaximal dorsiflexion angle and stiffness of the muscle-tendon unit were significantly decreased after both interventions. However, none of the assessed parameters significantly differed between the SS + ES and SS trials. These results show that 5 minutes of SS increases ankle ROM and changes the passive properties of the muscles. However, there is no additional effect of adding ES to SS.

Combined Static Stretching and Electrical Muscle Stimulation Induce Greater Changes in Range of Motion, Passive Torque, and Tendon Displacement Compared with Static Stretching

“…This position was held for 60 s, and then the footplate was returned to the −30°. This procedure was repeated five times without a rest [ 14 , 15 ]. Subjects were instructed to relax completely and not to offer any voluntary contraction.…”

“…Performing SS during muscle contraction by ES could potentially enable stretching intensity to be increased by increasing the pain threshold. Two previous studies investigated the acute and chronic effect of SS combined with ES (SS+ES) on flexibility and muscle strength [ 14 , 15 ]. The results revealed no significant difference in stretching intensity between the SS+ES and SS groups, although the SS+ES group exhibited a greater stretching angle in the first 4 weeks of an 8-week intervention compared with SS group [ 14 ].…”

“…The results revealed no significant difference in stretching intensity between the SS+ES and SS groups, although the SS+ES group exhibited a greater stretching angle in the first 4 weeks of an 8-week intervention compared with SS group [ 14 ]. The other study that examined the acute effect of SS+ES matched the stretching angle between combined and SS trials [ 15 ]. This previous study did not focus on examining the difference in stretching intensity between trials.…”

“…SS+ES is a similar contraction pattern to eccentric contraction (i.e., muscle was stretched in length by SS while being contracted by ES), and may affect not only muscle stiffness, but also tendon stiffness. A previous study reported that both SS+ES and SS trials did not change muscle stiffness [ 15 ]. However, this previous study did not assess tendon stiffness [ 15 ].…”

“…A previous study reported that both SS+ES and SS trials did not change muscle stiffness [ 15 ]. However, this previous study did not assess tendon stiffness [ 15 ]. Additionally, other passive properties, such as displacement of the muscle or tendon, would be expected to be affected differently between SS+ES and SS alone.…”