جستجوی مقالات مرتبط با کلیدواژه "بار خارجی" در نشریات گروه "پزشکی"

Objectives :

Due to the decline in the function of balance system in older adults and the importance of having an active old age, it is very important to maintain independence during daily living activities such as shopping, holding and carrying an external load. This study aims to determine the effect of external load magnitude and holding mode on the postural sway during standing in healthy community-dwelling older adults.

Methods & Materials:

 In this quasi-experimental study, 15 healthy community-dwelling older adults in Tehran, Iran (7 men and 8 women) with a mean age of 71.53±6.18 years who were independent in daily living activities such as shopping and carrying shopping bags were enrolled using a conveneince sampling method. The independent variables were holding manual loads with a magnitude of 0%, 5%, 10%, 15%, and 20 % of body weight in symmetrical (both hands) and asymmetrical (dominant or non-dominant hand) conditions, standing still on the force plate for 30 seconds. Dependent variables included the amount and velocity of the displacement of the center of pressure (COP) in two anteroposterior and mediolateral directions and the area of the COP displacement.

Results:

 The effect of holding manual loads symmetrically and asymmetrically and the manual load magnitude on the amount and velocity of COP displacement in anteroposterior direction was signifcant, while their interaction effect was not significant on any variables. The paired t-test results showed that the amount and velocity of COP displacement in anteroposterior direction at asymmetric condition was significantly different compared to the symmetrical condition, but there was no significant difference between holding with dominant and non-dominant hands. The amount of COP displacement in anteroposterior direction with 5%, 10%, 15% and 20% of body weight were higher and statistically significant compared to the load magnitude of 0% (P<0.05). The effects of load holding mode and load magnitude were not statistically significant on any of the COP variables in the mediolateral direction. 

Conclusion:

 Aging, Postural balance, External load Holding external loads asymmetrically with any magnitudes can increase the amount and velocity of COP displacement in the anteroposterior direction. For preventing falls, it is recommended for the elderly to pay attention to the fact that holding an external load with two hands is less challenging to the balance system than holding with one hand, whether dominant or non-dominant. In terms of the load magnitude, an external load with 5% of body weight can challenge the balance system compared to the situation without external load. With some exceptions, there is no difference between loads of 5%, 10%, 15% and 20% of body weight.

Lumbar curvature is an important factor in posture and body movement that help us to understand low back pain problems. The aim of this study was evaluation of external load and trunk posture effect on lumbar curvature under static condition.

This study is an interventional, quasi-experimental and case-control study. Ten women with non specific chronic low back pain and ten matched without low back pain women were participated in this study. We used simple and non random method for sampling. Two clinometers sensors were used to evaluate lumbar curvature. Six static tasks while holding three levels of load (0, 6, 12 Kg) and two levels of trunk position (neutral and 30 degree of flexion) were simulated for subjects. Data were analyzed by using Kolmogroff-Smirnoff, ANOVA (Repeated Measurement) and independent T-test.

Findings revealed lumbar lordosis in patients with low back pain does not change to kyphosis while increasing external load from 0kg to 6kg and 12kg in neutral trunk position (P<0.05).

Dysfunction in passive system due to soft tissue disorder, afraid of pain, changes trunk muscles recruitment and reduction of moment arm are likely reasons for increased lumbar lordosis in patients with low back pain during loading.