Morgana Alves de Britto

Does skin stimulation compensate impairments in postural control after ankle plantar flexors fatigue

It has been suggested that skin stimulation using tape glued to the skin over the Achilles tendon helps to improve postural control. It was recently shown that these effects might emerge only after muscle fatigue and not during non-fatigue standing. Here we tested the influence of skin stimulation on postural control before and after fatigue of ankle plantar flexors. Eighteen subjects stood quietly on a force plate while the center of pressure was monitored before and after fatigue of ankle plantar flexors muscles, with and without medical tape glued to the skin over the Achilles tendon. Our results suggested main effects of tape stimulation before fatigue (P<.05) and significant effect of tape stimulation after fatigue only for amplitude of center of pressure in the anteroposterior direction. The novelty of our study is that most of the center of pressure variables are improved by skin stimulation when the ankle plantar flexors are not fatigued. Therefore the benefits of tape stimulation during fatigue condition are questionable.

Quadriceps and hamstrings prelanding myoelectric activity during landing from different heights among male and female athletes

ACL tear is a major concern among athletes, coaches and sports scientists. More than taking the athlete away from training and competition, ACL tear is a risk factor for early-onset of knee osteoarthritis, and, therefore addressing strategies to avoid such injury is pertinent not only for competitive athletes, but for all physically active subjects. Imbalances in the prelanding myoelectric activity of the hamstrings and quadriceps muscles have been linked to ACL injuries. We investigated the effect of landing from different heights on prelanding myoelectric activity of the hamstrings and quadriceps muscles in recreational athletes. Thirty recreational athletes (15 male and 15 female) performed three bilateral drop jumps from two different heights; 20cm and 40cm while myoelectric activity of the vastus medialis, rectus femoris, biceps femoris and medial hamstrings were collected. When increasing the height of drop landing tasks prelanding normalized myoelectric activity of the quadriceps was increased by 15-20% but no significant changes were found for the hamstrings. Female athletes exhibited higher activity of the medial hamstrings compared to their male counterparts. We concluded that increasing the height of drop landing tasks is associated with increased myoelectric activity of the quadriceps but not the hamstrings in recreational athletes. These differences in muscle activity may be related to increased risk for ACL injury when the height is increased. Female athletes demonstrated higher recruitment of the medial hamstrings.

Leg skin stimulation can be a strategy to improve postural control in the elderly

Previous studies suggested that skin stimulation by using medical tape glued to the skin over the Achilles tendon can improve postural control in young adults. Such strategy can be valuable if helping to improve postural control in the elderly. Here, we tested the effects of skin stimulation on the postural control of elderly while standing barefoot. Twenty-two voluntary elderly had postural control assessed under different conditions of skin stimulation. Center of pressure was monitored while they stood quietly barefoot on a force plate during standing with and without medical tape glued to the skin over the Achilles tendon. There were effects of skin stimulation for anteroposterior amplitude of center of pressure displacement, mediolateral amplitude of center of pressure displacement, and area of the ellipse for 95% of center of pressure data (P<.05). These results are promising considering that skin stimulation by using medical tape is feasible even for low incoming subjects and possible to self manage for improvements in postural control.

Effect of a compressive garment on kinematics of jump-landing tasks.

Abstract de Britto, MA, Lemos, AL, dos Santos, CS, Stefanyshyn, DJ, and Carpes, FP. Effect of a compressive garment on kinematics of jump-landing tasks. J Strength Cond Res 31(9): 2480–2488, 2017—During jump-landing tasks, knee kinematics such as excessive valgus have been linked to knee injury in females. We determine the influence of a compressive garment on knee valgus during landing. Physically active women (n = 27, mean age 23 years) performed 4 different jump-landing tasks with 2 apparel conditions (compressive garment and regular sports shorts). Kinematic data were collected to determine knee flexion and valgus angles and the maximum jump height. Results showed that the compressive garment decreased knee flexion and knee valgus range of motion, without significant changes in the maximum jump height. As a practical application, we suggest that compression could be a strategy to reduce dynamic valgus without influencing jump performance, which motivates further study of its potential for knee injury prevention.