EFFECT OF MODIFIED HIGH INTENSITY INTERVAL TRAINING ON FAT LOSS

Exercise has multiple health benefits and is a critical component in managing overweight and obesity. High Intensity Interval Training (HIIT) involves brief high-intensity anaerobic exercise followed by rest or very low intensity exercise. 24 men and women (age 18–60 years) volunteered to participate in a 6 weeks of modified HIIT exercises program where whole body functional training exercises was provided. Their body weight, body mass index, waist to hip ratio and skin fold fat were measured at the beginning and at the end of the 6 weeks duration . Statistical significance was found between the variables at p < 0.05. The results showed that a Modified HIIT exercise Program based on Body weight training results in considerable decrease in level of sub-cutaneous adiposity up to 77.8%. Obesity and overweight have become complex pandemic disorders where in physical inactivity and lack of time to exercise plays a major role leading to various complications. Reduction in adiposity through structured exercises protocols will improve body composition and Cardio-metabolic health . Novel interventions such as modified HIIT serve as the perfect pathway to address the time factor and enhancement of physical activity as well. The results of the current study showed that six week modified high intensity interval training led to a significant decrease in the body’s adiposity. There was a considerable reduction in the BMI, WHR and the sum of skin folds post the six weeks of our exercise protocol. The direct effect of exercise on level of adiposity is unknown still. Yet, studies have made successful attempts in identifying the amount of fat lost due to exercise. Boudou et al. (2003) and Mourier et al . (1997), showed 18% reduction of subcutaneous fat. Similarly, Trapp et al. (2008), found 10% decrease and Tremblay et al . (1994), found 15% decrease in adiposity. Our study showed 77.8% decrease in subcutaneous fat levels. However our result was interpreted using the sum of skin folds rather than using any kind of radiological imaging source as supported by some of these authors.

People who were overweight and obese were considered for the study. Unhealthy people with co-morbids(such as musculo-skeletal injuries, cardiac patients, etc.) and unwilling participants were excluded from our study. All participants participated voluntarily and adequate knowledge regarding the study setting was explained to them. Information about the level of physical activity and health condition was obtained using a Physical Activity Readiness questionnaire (PAR-Q). Participants were stratified on a median age of 18 to 60 years and a BMI of ≥26. They were prescribed HIIT exercise for four days per week until six weeks. The participants (both females and males) characteristics included age (M = 37.63 ±12.79 years), height (M = 163.42 ±10.04) weight (M = 80.58 ±12.90 kg), Body Mass Index (30.30 ±2.62 kg/m 2 ), waist to hip ratio (M = 1 ±0.10) and sum of skin folds fat (M = 160.08 ±24.65).
Overall subject characteristics of pre-test and post-test values on individual variables of the participants (both men and women) had significant changes as seen on Tables 2 and 3 respectively.
Skin folds were measured using a Harpenden skin fold caliper and a seven-site ISAK method (biceps, triceps, subscapular, abdomen, supra iliac, mid-thigh and calf) was used to calculate the sum of skin fold fat value. All the population were considered as overweight/ obese according to the BMI and skin fold measurements.
The exercises consisted of floor based high intensity functional exercises followed by a short period of complete rest. Each participant underwent a series of exercises protocol as follows: 1. Warm up = 5 minutes. 2. Modified HIIT exercises = 15 minutes. 3. Stretching and cool down = 5 minutes.
The modified HIIT exercises were designed as whole body functional workouts. After completing the warm up session, the participants would perform a series of whole body modified HIIT exercises comprising of jumping jacks, squats, pushups, crunches, triceps dips, plank, same spot high knee running, lunges, side plank, v-sit hold, mountain climber and burpees. These are short, rapid series of exercises using one's own body weight. The participants performed these exercises for a time period of 30 seconds followed by 15 seconds of rest interval throughout the exercise regimen time of 15 minutes, for 4 days per week for 6 weeks. As the week progressed the participants were encouraged to repeat this exercise cycle as many as possible within the maximum stipulated time of 15 minutes.
A rating of perceived exertion was measured using the modified Borg scale, so as to ensure that the participants were within the exercise tolerance limits, as devised by the scale. The participants were given the right to stop the exercise session if they felt the intensity was reaching beyond their limit.
As this was an exercise intervention based study, participants were counselled to take a nutrient rich food intake not giving particular emphasis to their daily caloric intake, nor calculating macro/micro nutrient levels. However, participants were strictly advised to avoid junk food and processed food.

Data Analysis
At the end of six weeks, all participants were measured with a post data comprising of weight, BMI, WHR and skin fold fat levels. Data was analyzed using SPSS statistical software. Paired t-test was performed to identify the intergroup comparison. The significance level was considered at α = 0.05.

Results
The aim of this study was to implement a home based effective weight loss program through whole body functional exercises. As can be seen in Table 1, the variables such as body weight, waist-hip ratio (WHR), body mass index (BMI) and sum of skin folds were analysed for an inter group comparison. Statistical significance was found between the variables of BMI, WHR, body weight and sum of skin fold values. The results showed that after exercise interventions there is considerable decrease in the level of adiposity and body weight as well. Moreover, we noticed that there was 77.8% decrease (Figure 1) in the subcutaneous skin fold fat levels after the completion of 6 weeks of exercise regimen.

Discussion
The results of the current study showed that six week modified high intensity interval training led to a significant decrease in the body's adiposity. There was a considerable reduction in the BMI, WHR and the sum of skin folds post the six weeks of our exercise protocol. The direct effect of exercise on level of adiposity is unknown still. Yet, studies have made successful attempts in identifying the amount of fat lost due to exercise. Boudou et al. (2003) and Mourier et al. (1997), showed 18% reduction of subcutaneous fat. Similarly, Trapp et al. (2008), found 10% decrease and Tremblay et al. (1994), found 15% decrease in adiposity. Our study showed 77.8% decrease in subcutaneous fat levels. However our result was interpreted using the sum of skin folds rather than using any kind of radiological imaging source as supported by some of these authors.
Majority of our research goal was focused on estimating the amount of fat lost due to HIIT exercises than identifying the right pattern of exercise. Many authors have devised exercise strategies based on aerobic and anaerobic exercises Park et al., 2003;Johnson, Sachinwalla, Walton, Smith, Armstrong, Thompson, George, 2009). Some authors used different exercises forms to combat obesity (Strasser, Schobersberger, 2011;Schoenfeld, 2011). We narrowed our approach towards HIIT exercises that covered whole body rather than isolated set of muscular exercises. This apart, several studies have proved the advantages of HIIT exercise (Zhang et al., 2015;Heinrich et al., 2014;Kordi, Choopani, Hemmatinafar, Choopani, 2013 ), of which, short term HIIT exercises have found to produce better results in fat reduction than any other form of exercise (Lanzi et al., 2015;Panissa, Alves, Salermo, Franchini, Takito, 2016). Such short term exercise of high intensity pattern, if delivered accurately, has shown better results in losing adiposity.
All the HIIT exercises mentioned in our study are compound multi-dimensional workouts. They provide collective benefit to the participant rather than focusing on individualizing the muscle/body part worked. There are no consensus literature available as to what constitutes a true HIIT protocol (Hood, Little, Tarnopolsky, Myslik, Gibala, 2011). Thus, we designed a modified HIIT protocol which would be realistic for our participants to complete, and also is evidence based (Chandler, Stringer, 2020) .
Adiposity is a complex multifactorial mechanism involving genetic, metabolic, physiological, psycho-social and environmental cross links. The adipose tissue, though considered a 'toxic tissue' is found fundamental to the primary life-history functions of the human body (Wells, 2012). Hence, identifying the accurate ways to enhance such functions is essential. Though HIIT exercises provided ways to reduce excess adiposity, the efficacy of such exercises are still a point to ponder. One way to identify such efficacy was by estimating the aerobic capacity through Vo2 max, which in turn might be a costly factor. There is sufficient evidence to prove the effectiveness of HIIT on aerobic and cardiovascular factors (Garcia-Hermoso, Cerrillo-Urbina, Herrera-Valenzuela, Cristi-Montero, Saavedra, Martinez-Vizcaino, 2016). We however aimed at estimating the adiposity alone, cost effectively, rather than measuring aerobic or cardio vascular factors that require usage of various technology and gadgets. Hence, the anthropometric indices such as BMI, skin fold fat and WHR served as a better feedback in estimating the acute responses to HIIT exercises. We found considerable difference in the BMI and WHR post our exercises regimen.
Decrease in body composition can be considered as a key factor in delivering HIIT programs. Though there is sufficient evidence on reduction of body composition in young and adolescent participants (Costigan, Eather, Plotnikoff, Taaffe, Lubans, 2015), this study presents a diversified age group (Table 2 and Table 3) showing variance in body composition measures post the exercise period. Various studies have utilized the option of diet interventions in their program (Clark, 2015;Arad, DiMenna, Thomas, Tamis-Holland, Weil, Geliebter, Albu, 2015). We did not recommend any nutritional or dietary recommendations to our participants. All our participants were advised to follow their regular dietary pattern without any specific caloric intake recommendations/restrictions. This served as a highlight to determine the effectiveness of our program specifications which was devoid of any diet prescription. Our present study may be used as a preliminary research in estimating the level of adiposity loss using modified HIIT exercises.

Limitations
The key limitation of our study is the mode of measuring the level of adiposity. Though it is a proven fact that radiological imaging provides congruent evidence in estimation of body fat, we chose a cost effective way through measuring the skin fold fat levels. It did precisely provide body's adiposity levels, yet, specific adaptations to the exercise demands are unknown. Another limitation is the estimation of the effectiveness of the modified HIIT exercises offered to the participants. The exercises mentioned were scientifically proven/accepted list of exercises used by various researchers. However, individual efficacy of these exercises looks immeasurable. This is mainly due to the multi-dimensional benefit of each exercise. For example, doing a plank not only improves the core muscle strength, also, it provides equal support to the arms, elbows, back and toes. Hence, analyzing the micro effect of such multi-dimensional exercise is impractical. The diversified age group did show significant decrease in adiposity levels. Yet, age wise classification was harder to achieve without radiological investigations. Considering the technological advancement in today's world, we believe that these sustained adaptations such as fat loss due to modified HIIT exercises would become a handy tool in the days to come.

Conclusion
This preliminary study suggests that supervised six weeks of high intensity interval training connotes in achieving loss of adiposity among a diversified age group. The subcutaneous fat lost due to modifications in musculoskeletal parameters through six weeks of exercise training was firmly supported by significant decrease in anthropometric parameters as well. A multi-dimensional exercise regimen such as this could pave way for more time saving yet result oriented protocols in controlling obesity in the near future.