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BACKGROUND: Rate of force development scaling factor (RFD-SF) is used to assess neuromuscular quickness across submaximal levels. It has been suggested that such metric would be associated with the magnitude of the agonist muscle activation and with the level of simultaneous antagonist muscle group activation, i.e., agonist-antagonist coactivation. AIM: To examine the associations between 1) the RFD-SF and the rate of agonist muscle activation scaling factor (RAgMA-SF) and 2) the RFD-SF and the agonist-antagonist coactivation. METHOD: Eleven healthy and physically active subjects (7 men and 4 women, aged between 18 and 22 years) performed maximal strength tests of the knee extensors and flexors and a test that involved the production of brief submaximal force pulses of the knee extensors. The force exerted was recorded by a load cell and the electromyographic activities of the vastus lateralis and biceps femoris muscles were obtained during the tests. In the brief force pulses test, individuals were asked to produce around 120 submaximal force pulses that ranged between 20 to 80% of their maximum force value, while trying to produce each force pulse as fast as possible. The values of RFD-SF, RAgMA-SF of the vastus lateralis muscle, and a coactivation index (ICOA) were computed. RESULTS: The RFD-SF is strongly associated with the RAgMA-SF (r=0.74; p=0.009) but not with the ICOA (r=0.29; p=0.38). CONCLUSION: The RFD-SF is directly associated with the rate of agonist muscle activation and is not affected by the degree of coactivation between agonist and antagonist muscles. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Motor Behavior is the property of Brazilian Journal of Motor Behavior and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Brazilian Journal of Motor Behavior is the property of Brazilian Journal of Motor Behavior and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Brazilian Journal of Motor Behavior is the property of Brazilian Journal of Motor Behavior and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Brazilian Journal of Motor Behavior is the property of Brazilian Journal of Motor Behavior and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Partial body weight support (BWS) systems have been broadly used with treadmills as a strategy for gait training of individuals with gait impairments. Considering that we usually walk on level ground and that BWS is achieved by altering the load on the plantar surface of the foot, it would be important to investigate some ground reaction force (GRF) parameters in healthy individuals walking on level ground with BWS to better implement rehabilitation protocols for individuals with gait impairments. Objective: To describe the effects of body weight unloading on GRF parameters as healthy young adults walked with BWS on level ground. Method: Eighteen healthy young adults (27±4 years old) walked on a walkway, with two force plates embedded in the middle of it, wearing a harness connected to a BWS system, with 0%, 15%, and 30% BWS. Vertical and horizontal peaks and vertical valley of GRF, weight acceptance and push-off rates, and impulse were calculated and compared across the three experimental conditions. Results: Overall, participants walked more slowly with the BWS system on level ground compared to their normal walking speed. As body weight unloading increased, the magnitude of the GRF forces decreased. Conversely, weight acceptance rate was similar among conditions. Conclusions: Different amounts of body weight unloading promote different outputs of GRF parameters, even with the same mean walk speed. The only parameter that was similar among the three experimental conditions was the weight acceptance rate. [ABSTRACT FROM AUTHOR]

Background: Ear Acupuncture (EA) is a form of acupuncture in which needles are applied to the external ear and has been used in multiple painful conditions. Low back pain (LBP) is highly prevalent in active individuals and causes high economic burden to health systems worldwide. LBP affects the person's ability to keep balance, especially in challenging conditions. Objective: The aim of the study was to examine the effects of a single session of EA on pain intensity and body sway during postural tasks. Method: Eighty adults with LBP and pain intensity equal to or greater than 4 (0-10 scale) were randomly allocated (1:1) to EA group (EAG) or placebo group (PG). Initially, the level of pain intensity was assessed. Next, participants stood still on a force plate either with feet in parallel or in semi-tandem and with eyes open or closed. Then, the EAG was treated with EA for 20 min and the PG was treated with detuned ultrasound. After the treatment, pain intensity was assessed again and the postural test was repeated. Pain intensity was the primary outcome and center of pressure sway area and speed were the secondary outcomes measured. Results: Results revealed that pain intensity decreased in both groups after treatment, but decreased more in the EAG. For postural control, no effect of treatment and no interaction between treatment and postural condition on body sway were found. Conclusion: Those findings indicate that EA is better than placebo to reduce pain, but neither treatment has any effect on postural control. [ABSTRACT FROM AUTHOR]