Half Of Movement Research Articles

Muscle activity of upper and lower trapezius and serratus anterior during unloaded and maximal loaded shoulder flexion and extension

Altered scapular muscle activity is mostly described under unloaded and submaximal loaded conditions in impingement patients. However, there is no clear evidence on muscle activity with respect to movement phases under maximum load in healthy subjects. Therefore, this study aimed to investigate scapular muscle activity under unloaded and maximum loaded isokinetic shoulder flexion and extension in regard to the movement phase. Fourteen adults performed unloaded (continuous passive motion [CPM]) as well as maximum loaded (concentric [CON], eccentric [ECC]) isokinetic shoulder flexion (Flex) and extension (Ext). Simultaneously, scapular muscle activity was measured by EMG. Root mean square was calculated for the whole ROM and four movement phases. Data were analyzed descriptively and by two-way repeated measures ANOVA. CPMFlex resulted in a linear increase of muscle activity for all muscles. Muscle activity during CONFlex and ECCFlex resulted in either constant activity levels or in an initial increase followed by a plateau in the second half of movement. CPMExt decreased with the progression of movement, whereas CONExt and ECCExt initially decreased and either levelled off or increased in the second half of movement. Scapular muscle activity of unloaded shoulder flexion and extension changed under maximum load showing increased activity levels and an altered pattern over the course of movement.

KINEMATIC DIFFERENCES IN LUMBOPELVIC AND HIP MOVEMENT PATTERNS DURING A LOWER LIMB MOVEMENT TEST BETWEEN TWO GROUPS OF PEOPLE WITH LOW BACK PAIN

Increased lumbopelvic motion during limb movements’ tests was reported in low back pain (LBP) patients with and without rotational demand activities. The aim of this study was to compare lumbopelvic movement pattern between two groups of LBP patients with and without rotational demand activity during active hip external rotation test. A total of 39 patients with non-specific chronic LBP participated in this study. Patients were allocated into two groups, in first group 15 subjects (mean [Formula: see text] years) with rotational demand activities such as tennis, squash and golf, and in second group 24 subjects (mean [Formula: see text]) without rotational demand activities participated in current study. Kinematic data from lumbopelvic-hip region during active hip external rotation test (AHER) were collected by a 3D motion analysis system. Variables including range of motion (ROM) of hip external rotation, pelvic rotation, pelvic rotation during first half of hip rotation motion and timing of pelvic-hip movement were calculated by MATLAB software for both sides and after this, independent t-test was used to compare the variables between two groups of study. The mean lumbopelvic rotation in lower extremities tests for both sides and lumbopelvic rotation in the dominant limb external rotation test in the patients with rotational demand activities were significantly more than other group ([Formula: see text]). During dominant lower limb movement test, pelvic rotation in first half of movement and in patients with rotational activities was greater than in non-rotational group but hip rotation was statistically lesser than other group ([Formula: see text]). Other variables between the two groups were not significantly different ([Formula: see text]). The result of the study suggest that LBP patients who have rotational demand sports activities may move their lumbopelvic region in a greater magnitude during the AHER test than LBP people without rotational demand activities. Therefore, Lumbopelvic movement pattern in different groups of patients with LBP and based on their specific activities is different with each other.

Afferent Information for Motor Control: The Role of Visual Information in Different Portions of the Movement.

The question addressed in the present study was whether subjects (N = 24) can use visual information about their hand, in the first half of an aiming movement, to ensure optimal directional accuracy of their aiming movements. Four groups of subjects practiced an aiming task in either a complete vision condition, a no-vision condition, or in a condition in which their hand was visible for the first half [initial vision condition (IV)] or the second half of the movement [final vision condition (FV)]. Following 240 trials of acquisition, all subjects were submitted to a transfer test that consisted of 40 trials performed in a no-vision condition. The results indicated that seeing the hand early in movement did not help subjects to optimize either directional or amplitude accuracy. On the other hand, when subjects viewed their hand closer to the target, movements resulted that were as accurate as those performed under a complete vision condition. In transfer, withdrawing vision did not cause any increase in aiming error for the IV or the no-vision conditions. These results replicated those of Carlton (1981) and extended those of Bard and colleagues (Bard, Hay, & Fleury, 1985) in that they indicated that the kinetic visual channel hypothesized by Paillard (1980; Paillard & Amblard, 1985) appeared to be inoperative beyond 40deg of visual angle.

THE MECHANICS OF THE HIND FOOT IN CLUB FOOT AS DEMONSTRATED RADIOGRAPHICALLY

1. Lateral radiographs of fifty-seven club feet and seventeen normal feet were taken in forced flexion and forced extension. On these, the arcs traversed by the talus, the sole and the calcaneus were measured, as was the talo-calcaneal angle. 2. It was found that the ankle in club feet usually contributed more than half of the total sagittal movement of the foot. 3. Occasional cases were encountered in which the ankle was so damaged that it contributed only half or less than half of this movement. In such cases wedge excision of the ankle joint is theoretically justified in preference to wedge tarsectomy. 4. The talo-calcaneal angle is much reduced in club foot, and this element of deformity is extremely resistant to manipulative treatment. The reasons for this and a possible method of treatment are discussed.