Comparison of Frequency of Muscular Activity during Walking in Overweight People with Pronated Foot with Healthy Ones

Background &

Overweight and obesity are defined as abnormal or excessive fat accumulation that may impair health. Body mass index (BMI) is a simple index of weight-for-height that is commonly used to classify overweight and obesity in adults. It is defined as a person's weight in kilograms divided by the square of his height in meters (kg/m2). In 2019, an estimated 38.2 million children under the age of 5 years were overweight or obese. Once considered a high-income country problem, overweight and obesity are now on the rise in low- and middle-income countries, particularly in urban settings. In Africa, the number of overweight children under 5 has increased by nearly 24 % percent since 2000. Almost half of the children under 5 who were overweight or obese in 2019 lived in Asia. Over 340 million children and adolescents aged 5-19 were overweight or obese in 2016. The prevalence of overweight and obesity among children and adolescents aged 5-19 years has risen dramatically from just 4 % in 1975 to just over 18 % in 2016. The rise has occurred similarly among both boys and girls: in 2016 18 % of girls and 19 % of boys were overweight. While just under 1 % of children and adolescents aged 5-19 were obese in 1975, more 124 million children and adolescents (6 % of girls and 8 % of boys) were obese in 2016. Overweight and obesity are linked to more deaths worldwide than underweight. Globally there are more people who are obese than underweight Raised BMI is a major risk factor for cardiovascular diseases Childhood obesity is associated with a higher chance of obesity, premature death and disability in adulthood. But in addition to increased future risks, obese children experience breathing difficulties, increased risk of fractures, hypertension, and early markers of cardiovascular disease, insulin resistance and psychological effects. Overweight and obesity are among the most important concerns and threats to public health and probably the most common malnutrition problem in the world and is known as a chronic disease in developed and developing countries and has a dramatic increase (1). Obesity is a risk factor for disorders such as hyperlipidemia, hypertension, type 2 diabetes, renal complications, respiratory disease, coronary heart disease, stroke, etc. (2). Deviation from normal physical posture can be effective in losing beauty and also reducing a person's mechanical performance and predispose a person to muscle and nerve injuries. In the pronation of the foot, the internal arch of the foot is reduced, and then the navicular bone falls and protrudes on the inner surface of the foot, which can also cause other anatomical abnormalities (10). The aim of this study was to compare frequency content of selected lower limb muscles during walking in overweight people with pronated foot, pronated feet individuals without overweight and healthy control ones.

The research is a semi-experimental type. The study design of the present study is cross sectional. The statistical sample of the present study include 15 healthy adult females, 15 pronated feet adult females without overweight, and 15 overweight adult females with pronated feet. To record the ground reaction forces data, a Bertec force plate device with a sampling rate of 1000 Hz was used. The electromyography data was recorded using a wireless biometric electromyography device with 8 channels. The 20 Hz cut of frequency was used to smooth ground reaction force data. Ground reaction force data were used to determine the beginning and end of the gait stance phase. Selected lower limb muscles include tibialis anterior, gastrocnemius, vastus lateralis, vastus medialis, rectus femoris, biceps femoris, semitendinosus, and gluteus medius. The electrodes were attached on selected lower limb muscle in accordance with SENIAM protocol. Before, electrode placement, the shaving process was done. The walking trials were done at constant speed. The walking stance phase was divided into loading phase, mid-stance phase, and push off phase. Median frequency of EMG data was selected as a dependent variables. Normal distribution of data was confirmed using a Shapiro-Wilk test. One way ANOVA test was used for statistical analysis. All analysis were done at SPSS software. Significant level was set at p<0.05.

Results revealed that the frequency content of vastus lateralis muscle during loading phase in the pronated feet group was greater than healthy group (p = 0.02). Also, results revealed that the frequency content of vastus lateralis muscle during loading phase in the pronated feet group with overweight was greater than pronated feet group (p < 0.01). The frequency content of rectus femoris muscle during loading phase in the pronated feet group was greater than healthy group (p = 0.04). Results revealed that frequency content of vastus lateralis, vastus medialis, biceps femoris, and gluteus medius during mid stance phase in pronated feet group was lower than healthy control ones (p < 0.02). Also, the frequency content of tibialis anterior muscle during mid stance phase in overweight group with pronated feet was lower than healthy control ones (p < 0.01). The frequency content of rectus femoris muscle and semitendinosus muscle during push off phase in pronated feet group was greater than that healthy control ones (p < 0.01). The frequency content of rectus femoris and semitendinosus muscles during push off phase in overweight group with pronated feet group were lower than that pronated feet group (p < 0.03).

The frequency content of quadriceps muscles during loading phase in the pronated foot group with overweight was similar to healthy group. Therefore, the compensatory mechanism in the frequency content of quadriceps muscles in the pronated foot group with overweight does not occur to reduce impact force. Moreover, the frequency content of rectus femoris muscle during loading phase in the pronated foot group was greater than healthy group. Results revealed that frequency content of vastus lateralis, vastus medialis, biceps femoris, and gluteus medius during mid stance phase in pronated feet group was lower than healthy control ones. Also, the frequency content of rectus femoris muscle and semitendinosus muscle during push off phase in pronated feet group was greater than that healthy control ones. The frequency content of rectus femoris and semitendinosus muscles during push off phase in overweigh with pronated feet group were lower than that pronated feet group.