Obesity, defined by American College of Sports Medicine (ACSM) is an excessive amount of adipose tissue that presents a risk to individual’s health. Overweight & obesity are rapidly increasing in countries like India. The prevalence of obesity in the world for women is about 38.5% and exceeds more than 50% in some countries. As in India, the prevalence of obesity in women is 31.3 % and it has increased by 24.52% from the years 2006-2016 and is only increasing every year.
Body fat is adipose tissue (body fat) in abnormal constituent of the human body that serves the important function of storing energy as fat for metabolic demand. Body fat more than 24% in females is considered unhealthy and not fit and there are many causes and risk factors of increased body fat, which of few include eating more food than what body can use, not doing enough exercise and sedentary lifestyle. It is associated with numerous health risks like bone and joint problem, gallstones and liver problems, coronary heart disease, high blood cholesterol, high blood pressure, sleep apnoea, fatigue and poor attention Thus, to combat all these complications preventing the increase in fat mass by exercise is the best treatment option¬.
Body fat percentage is the body fat percentage (BFP) of a human or other living being is the mass of fat divided by body mass; body fat includes essential body fat and storage body fat. Essential body fat is necessary to maintain life and reproductive function. Storage body fat consist of fat accumulation in adipose tissue, part of which protects internal organs in the chest and abdomen. The body fat percentage is a measure of fitness level, since it is the only body measurement which directly calculates a person’s relative body composition without regards to heights or weight. American council on exercise (ACE) body fat % chart description for women ideal for 20-40 years are: essential fat 10-13%, athletes 14-20%, fitness 21-24%, average 25-31% and obese 32% and above.
The most common criteria used to determine overweight & obesity is by body mass index (BMI). The BMI values according to WHO are Normal BMI range 18-24.9, Overweight range 25-29.9, Obese grade I 30-34.5, Obese grade II 35-39.5 and Obese grade III >40.
Exercise is an important strategy to attenuate loss of function through the life cycle[1,4]. High intensity interval training (HIIT) and Strength Training can sustain ease of movement, Stimulate NEAT (non-excessive activity thermogenesis), and attenuate the accretion of fat mass. HIIT refers to activities such as walking or jogging with continuous, repetitive movement of large muscle groups for at least 10 minutes at a time. Strength Training on the other hand uses muscular strength to move a weight or to work against a resistive load, causing isolated, brief activity of a single muscle group and has received increasing attention in the last decade. Strength training improves muscular strength and endurance, enhances flexibility and body composition decreases the risk of cardiovascular diseases[7,20]. Numerous studies have been conducted on the effect of HIIT for fat loss by Nejmeddine Ouerghi, et al. and Maillard F., et al found significant decrease in body fat percentage [22,26]. and a very few studies have been done on the effects of strength training for fat loss by Leslie H. William et al. also found significant decrease in body mass.
Therefore, it is necessary to determine a better training program by combining HIIT & Strength training to reduce body fat composition in overweight and obese women.
NEED OF STUDY
Obesity levels continue to increase in both developed and developing countries and is associated with numerous health diseases, especially with the youth above poverty line tend to have improper habit of eating junk food with lack of self-control over eating with minimal or no physical activity.
Not only obese individuals but also normal BMI individuals tend to have higher body fat percentage, which is health warning . One of the main reasons of obesity is physical inactivity and it independently predicts and especially abdominal obesity in young adulthood.
As both exercise regime aid as a very good fat loss maneuver but the combined effect of both is rarely studied. Thus, to combat obesity by preventing the increase in fat mass by exercise and the need to find the best effect of fat loss we have undertaken this study.
AIM & OBJECTIVES
To study effect of HIIT & Strength training on body fat percentage in overweight and obese women.
- To find out the effects of HIIT & Strength Training on body fat percentage using body fat analyzer5.
- To find out the effects of HIIT & Strength Training on BMI1.
- To find out the effects of HIIT & Strength Training on waist-Hip ratio.
- To find out the effects of HIIT & Strength Training on BMR.
- H1: There is a statistical significant effect of HIIT & Strength training on body fat percentage.
- H0: There is no statistical significant effect of HIIT & Strength training on body fat percentage. METHODOLOGY
This study was undertaken in interest to find the effectiveness of HIIT & strength training combined effect on body fat percentage and BMI as well as Waist-Hip circumference and BMR. Within the age group of 20 to 45 years females for acquiring the type of exercise that is best for fat reduction, in which 37 participants were selected and there were 2 drop-outs due to discomfiture and irregularity.
Following the 6 weeks intervention the participants of the exercise group attained more than 10% reduction (Table 1) in the body fat percentage.
Recent studies have shown that the effect of HIIT alone is effective in reducing subcutaneous and abdominal fat than other type of exercises with a 5-7% reduction. HIIT has also shown to improve aerobic and anaerobic fitness[1,22], increased skeletal muscle capacity for fatty acid oxidation also according to ACSM it helps to burn more body fat in less time and burns few calories post exercise. Strength training on the other hand performed for 6 weeks and above showed significant decrease in abdominal fat, visceral fat and subcutaneous fat by a of 5% in 6 weeks therefore increase in lean muscle tissue through strength training increases the calories and fat burnt at rest, strength training strengthens muscle and demands more calories.
Various studies tested the effectiveness of HIIT & Strength training individually in reducing fat percentage, which showed significant decrease in body fat[8,11,15,21,22]. Matthew Monaco, et al. studied the effect of both HIIT & Strength training which showed effectiveness in reducing body fat than the exercise regime of HIIT & Strength training individually result in modest reduction in body fat percentage in young and middle aged women. The combined effect also induced fat oxidation during and after exercise and suppressed appetite .
Alongside body fat, there was extremely significant decrease in waist & Hip circumference and no significant difference in pre & post findings on waist-hip ratio.
There is increasing evidence that central obesity is more strongly correlated with cardiovascular disease than measures of general obesity therefore it is important to note that the combines exercise group decreased significant waist & hip circumference (Table 3). Whereas studies on Strength training have shown minimal significance in reducing waist & hip circumference. Perhaps the significant increase in the exercise duration of the combined group explains the findings.
There is also a significant increase in basal metabolic rate. Basal metabolic rate is an important indicator of health. BMR increase in response to 6 weeks of HIIT & Strength training combines exercise group (Table4) in conclusion, HIIT & Strength training combined provided a time-efficient stimulus to increase BMR in 6 weeks in healthy adults. Perhaps the most common cited reason for reduction in fat mass and body weight by exercise training is that basal metabolic rate theoretically increases as lean body mass increases[17,18,19,20].
In the present study, the effectiveness of HIIT & Strength training was extremely significant in reducing body fat percentage in overweight and obese women.
- Unable to keep a dietary record.
- The study did not have a control group so other than exercise training there can be other factors, which would have contributed to this result.
FUTURE SCOPE OF STUDY
- A dietary modification can be given along with exercise protocol.
- Further study can be done by adding conventional exercise protocol as control group vs HIIT and Strength Training on body fat percentage.
From the results of the study, we conclude that the 6 weeks HIIT & Strength Training program is found to be effective in reducing body fat percentage amongst overweight and obese women. There is decrease in waist & hip circumference and an increase in basal metabolic rate, which supports the findings of this study.