|Year : 2014 | Volume
| Issue : 4 | Page : 251-254
Biomechanical variation of joint angles in overweight females
Pooja P Popat, Ankur R Parekh
School of Physiotherapy, RK University, Rajkot, Gujarat, India
|Date of Submission||10-Aug-2014|
|Date of Decision||14-Oct-2014|
|Date of Acceptance||11-Nov-2014|
|Date of Web Publication||11-Dec-2014|
Pooja P Popat
30 Baasera Park, Near Rani Tower, Kalawad Road, Rajkot, Gujarat
Source of Support: None, Conflict of Interest: None
Background: An increase in body weight is considered to cause overload of the foot, which represents the interface between the body and ground. This can induce various stress and strain during walking that can predispose to overuse injuries of the lower limb. The purpose of the present study is to determine biomechanical variation of the joint angles of the lower limb such as calcaneal eversion (CE), gastrocnemius extensibility (GE), angle of toe-out (ATO), and Q-angle in overweight females. Methodology: The total of 25 overweight female subjects (body mass index [BMI] =25-29.9) were assigned as test group to determine biomechanical variation CE, GE, ATO and Q-angle. While 25 healthy female subjects (BMI = 18.5-24.9), were selected as a control group. CE and GE were measured in the prone position. While, Q-angle was measured in weight bearing and ATO was measured in walking position. Result: Independent Student's t-test was performed for comparing age, BMI, various angles among both normal and overweight female subjects. Significant increase in CE and ATO were found among overweight females as compared to normal females. While GE was significantly decreased among overweight female. Conclusion: Within limits of the present study, significant variation was found in CE, ATO (increase) and GE (decrease) in overweight females.
Keywords: Angle of toe-out, calcaneal eversion, gastrocnemius extensibility, overweight females, Q-angle
|How to cite this article:|
Popat PP, Parekh AR. Biomechanical variation of joint angles in overweight females
. J Obes Metab Res 2014;1:251-4
| Introduction|| |
In a normal weight individual, the major joints of the lower extremity are exposed to reaction forces of approximately three to six times body weight during locomotion (single leg stance phase). , It may be reasonable to hypothesize that obese individuals experience greater absolute loads at these joints than individuals of normal weight. 
Overweight and obesity are worldwide major health problem where body weight is >20% of the ideal. Overweight leads to obesity and there are many long-term debilitating effects of obesity that may impair the quality of life. These include cardiovascular disease, diabetes mellitus and various musculoskeletal disorders. 
Of these musculoskeletal disorders, foot problems in obese adults are most important. This may be due to the increased stress placed on the feet through the need to bear excessive mass.  The quadriceps angle (Q-angle) is an important indicator of biomechanical function in the lower extremity. There is an effect of excessive pronation on Q-angle.  Foot problems are frequent because the interface between body and ground is subjected to high stresses and load.  The foot provides a stable support for the body, attenuates impact and rotational forces, provides sensory information,  and combines flexibility and stability for propulsion of the body. , Such a mal-alignment is thought to place undue stress and strain on the joints, ligaments and muscles. 
One of the common muscle imbalances that affect the ankle joint is a tight gastrocnemius-soleus.  These muscles use 85% of their voluntary contraction during normal walking to help restrain the body's forward momentum by working eccentrically and concentrically. 
The purpose of present study is to determine biomechanical variation of the joint angles of the lower limb such as; calcaneal eversion (CE), gastrocnemius extensibility (GE), angle of toe-out (ATO) and Q-angle in overweight females. Furthermore, correlation among these angles was also determined in the present study.
| Methodology|| |
About Twenty-five overweight female subjects and 25 healthy female subjects visited Civil Hospital, Rajkot and Ramkrishna Ashram Physioyherapy Center, Rajkot during March-April 2014 were enrolled in the present study. The individuals with body mass index (BMI) value 18.5-24.9 were assigned as control group (Group A: Healthy controls) while individuals with BMI value 25-29.9 were assigned to the test group (Group B: Overweight) in the study. Those subjects with the use of external appliances, traumatic injury to lower limb in last 6 months, limb length discrepancy were excluded.
The measurements of various angles and BMI were performed by a single well-trained examiner.
Subject's height and weight were determined for calculating BMI as per Quetel's index:
BMI = weight (kg)/height (m 2 )
- Measurement of CE
- Measurement of GE
- Measurement of Q-angle
- Measurement of ATO.
Measurement of calcaneal eversion
Subtalar joint eversion was determined with subjects positioned prone with a lower half of the calf off the edge of the plinth. The axis of standard goniometer was placed between the malleoli in the frontal plane. The stationery arm of the goniometer was placed over the line on the posterior region of the calf, and a movable arm was placed over the line of calcaneum. The calcaneus was passively everted to obtain subtalar joint range of motion (ROM). This method of approach has shown good intrarater reliability with Elveru et al., reporting intraclass correlation coefficients of 0.75 for CE  [Figure 1].
Measurement of gastrocnemius extensibility
The subject was positioned in the prone position, and a marker was used for marking the fibular head, lateral malleolus, base of fifth metatarsal tuberosity and fifth metatarsal head. The axis of the goniometer was kept on the lateral border of the foot [Figure 2]. The zero position of dorsiflexion was defined as 90°° between the long axis of fibula and the lateral border of the foot. All measurements were recorded as the subjects achieved maximum dorsiflexion. 
|Figure 2. Measurement of gastrocmieus angel (gastrocnemius extensibility)|
Click here to view
Measurement of angle of toe-out
It represents the angle of foot placement. And it is formed by each foot's line of progression and line intersecting the center of heel and the 2 nd toe.  The subject was instructed to walk away. From the second footprint, three consecutive footprints were evaluated for ATO [Figure 3] and [Figure 4].
Measurement of Q-angle
It is an angle formed between a line connecting the anterior superior iliac spine to the mid point of the patella and a line connecting tibial tuberosity to the midpoint of the patella. It is measured in a standing position [Figure 5] and [Figure 6]. 
Statistical analysis of data was performed using Instat GraphPad computerized software. An independent student's t-test was performed for comparing CE, GE, ATO and Q-angle between Group A (normal) and Group B (overweight). The Pearson's correlation coefficient was calculated to establish an association between the variables within Groups A and B. p < 0.05 was considered to be statistically significant
| Result|| |
Significant increase in CE and ATO were found among overweight females (Group B) as compared to normal females (Group A). While, GE was found to decrease significantly among overweight females (Group B) as compared to normal females (Group A). Nonsignificant decrease in value of Q-angle was found in overweight females (Group B) as compared to normal females (Group A) [Table 1] [Figure 7]. While, different correlation was observed among different angles in both the groups [Table 2].
|Figure 7. Comparision of Variables between Group A and B. (CE=Calcaneal eversion; GE=Gastrocnemius Extensibility; ATO=Angle Of Toe-out)|
Click here to view
| Discussion|| |
Heel forces while walking increase as body weight increases.  Due to the excessive pronation subjects presenting with less GE, which causes shortening of the tendo-achilles and instability at the subtalar and midtarsal joints.  Charrette concluded that overweight subjects showed greater ATO as they have an increased foot flare while walking.  According to Kendall et al. in the weight bearing position, there is the flatness of the longitudinal arch, which is usually accompanied by out-toeing. 
There is a greater CE in subjects who are overweight, which can lead to less active ROM of ankle dorsiflexion. According to Charrette, excessive pronation is due to tight tendo-achilles (vide supra) or gastro-soleal equines.  By this, there is a negative correlation between CE and GE.
Tight tends-achilles can cause the eversion of the calcaneus.  And ATO increase due to contracture of the gastrocnemius and soleus.  By this, there is a positive correlation between CE and ATO. The same result proved by Chang et al. concluded that increased out-toeing increases pressure on the medial foot and provides mechanical force directed at the valgus foot. The in-toeing gait unloads the medial foot and increases the severity of the varus foot.  An out toe position was found in subjects with a tight gastrocnemius.  This result is found in overweight because toeing out in walking may result from tightness of tendo achilles.  This is likely to place strain on structures associated with the longitudinal arch as weight is transferred from heels to toes. 
Charrette concluded that there is a decrease in Q-angle is due to muscles commonly found to be tight include the quadriceps, hamstrings, iliotibial band and gastrocnemius.  There is increased weight has an effect on CE, ATO and GE and Q-angle. Kapandji conclude that the extra weight puts stress on the foot causing flattening of the arches.  Severely obese females have significantly greater rear foot motion and foot angle values than normal weight females  which can lead to certain dysmorphism of foot specially flat foot,  negative impact on balance and alteration in the gait. 
There are female participants only with age group of 24-45 years and normal and overweight (18-29.5) BMI included in this study are the limitations of the study.
| Conclusion|| |
Calcaneal eversion and ATO are more in the overweight whereas GE is less in overweight when compared with normal subjects. There is a negative correlation of GE CE and ATO. And positive between CE and ATO, GE and Q-angle. There is a negative correlation of GE and ATO and positive between calcaneus eversion and ATO.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7]
[Table 1], [Table 2]