Validity of a portable hanging scale to assess the isometric muscle strength during knee movement.

Inexpensive and practical equipment to assess muscle strength can disseminate objective measures, which can provide valid information to implement effective treatment and exercise training. The purpose of the study was to examine the instrumental validity of the hanging scale (HS) to assess the muscle strength during knee flexion and extension by comparing the peak force values to a standard equipment (laboratory-grade load cell [LLC]). Knee isometric strength was assessed on thirty-two subjects (16 women and 16 men, 22 [5] years, 171 [9] cm, 69 [15] kg, 23 [4] kg/m2). The knee flexion was tested by placing the volunteer's body in prone with the knee flexed at 90°. Knee extension was assessed with the volunteer seated on a chair with the feet resting on the floor, knees, and hips flexed at 90°. No differences were observed comparing the isometric peak forces between a laboratory-grade load cell and a HS (p > 0.05). The intraclass correlation coefficient (ICC)1,1 returned values above 0.90. The Cronbach's α test also returned values above 0.90 for all comparisons. Bland-Altman results showed high levels of agreement with low risk of bias. The HS appears to be a valid method to assess the knee isometric strength. The portability, the cost-effectiveness and the simple user-friendly system provides an effective way to assess the knee isometric strength.

Muscle excitation, force response, and efficiency during explosive force production after diacutaneous fibrolysis on lateral gastrocnemius of recreational athletes.

OBJECTIVE: Fibrous adhesions impair normal muscle mechanics. The present study aimed to assess lateral gastrocnemius muscle excitation, isometric force response, and neuromuscular efficiency during explosive force in plantarflexion before and after diacutaneous fibrolysis. METHODS: Thirty-five recreational athletes were allocated in the intervention group (n = 20) treated with diacutaneous fibrolysis, while the sham group (n = 15) was treated with placebo diacutaneous fibrolysis. Force response synchronized with surface electromyography during a plantarflexion task was collected. RESULTS: Differences between Pre- and Post-diacutaneous fibrolysis were observed for all variables, except for the placebo group. CONCLUSIONS: Diacutaneous fibrolysis was effective to increase force, muscle excitation, and neuromuscular efficiency on lateral gastrocnemius.

Pilates experience vs. muscle activation during abdominal drawing-in maneuver.

The purpose of this study was to compare the activation of deep abdominal and spine stabilizer muscles of subjects with and without Pilates experience. Twenty-three subjects were divided into a no-experience group (n = 13) and an experienced group (n = 10). The subjects performed three 12-s drawing-in maneuver trials at 50% TrA/IO maximal voluntary contraction (MVC). The experienced group presented greater activation of both muscles than the no-experience group (62% vs. 32% MVC for the TrA/IO, and 52% vs. 12% MVC for the LD, p < 0.001). The no-experience group had higher variability among trials and did not reach 50% MVC for the TrA/IO, while the experienced group was able to reach and keep the TrA/IO activation at or above 50% MVC. Pilates experience and muscle activation were strongly associated. Pilates trained subjects were able to sustain concomitant abdominal and low back muscle contraction during the drawing-in maneuver, while subjects with no Pilates experience were not able to reach the same levels of abdominal activation and did not present significant low back muscle co-activation.