A recent study by Vispute et al. (2011) supports the evidence from a study by Katch et al. (1984) from 30 years ago, that demonstrated exercises targeting the core were not successful in spot reduction of body fat around the stomach area. The subjects in the 2011 study were in their early to mid-twenties – the control group had 10 participants, age 22.49+0.97 with body fat percentages of 35.66+9.33. The exercise group had 14 subjects, with an average age of 24.50 +4.97 and body fat percentage of 35.98 + 8.86. 11 of the 14 subjects completed 100% of the sessions and the other three completed 80% of the sessions. The exercise group performed bent knee sit ups, lateral trunk flexion, leg lifts, oblique crunch, stability ball crunch, stability ball twist and abdominal crunch. On each of these exercises subjects completed 2 sets of 10 repetitions, 5 days a week for 6 weeks. The results were that there was no significant effect in total body fat percentage loss between the two groups.
|Body Weight (kg)
||70.4 + 9.8
||70.8 + 10.1
||68.9 + 10.2
||69.4 + 11.4
||24.5 + 3.6
||24.6 + 3.1
||24.7 + 3.1
||24.8 + 3.0
|Total Body Fat (%)
||35.6 + 9.3
||35.9 + 9.6
||35.9 + 8.8
||34.8 + 8.3
|Android Fat (%)
||43.1 + 9.3
||46.8 + 6.6
||43.5 + 9.1
||42.3 + 9.1
From Vispute et al. (2011) Body mass and composition before and after 6 weeks of abdominal exercise in control (n=10) and exercise (n=14) groups.
Research by Ramirez-Capillo et al. (2013) looked at spot reduction on the legs. Subjects completed a 12 week localised muscle endurance resistance training program for the leg muscles of their non-dominant leg. Subjects completed one set of leg presses per session – 10% 1 RM during weeks 1-4; 20% 1 RM during weeks 5-6 and 30% 1 RM during weeks 7-12 three times a week, thus completing 960-1,200 repetitions for their set, and with no rest between repetitions.
Ramirez-Capillo et al. (2013) found that although they targeted a specific body part, they reduced the whole-body fat by 0.7%. They also reported that the program resulted in a reduction in trunk and arm fat mass, greater than that observed in the trained leg. This study proved that you would be better off completing a rounded program to target fat loss on the whole body as attempting to spot reduce fat can cause body fat to be lost on areas you are not targeting.
These two studies prove that attempting to ‘spot’ reduce body fat is not worthwhile. The study by Ramirez-Capillo et al. (2013) does show that when a muscle group is trained, changes in fat mass can take place, but often on body parts which are not directly near the muscle being targeted.
So what should you do?
The biggest excuse for people not going to the gym is time and money, which is why spot reduction through abdominal exercises at home is a popular choice.
High Intensity Interval Training (HIIT) has, in recent years, emerged as a successful way to reduce fat from all over the body. This exercise protocol involves repeated bouts of exercise for as little as 8 seconds in some protocols, up to several minutes, separated by recovery periods. These recovery periods either involve low intensity exercise or none-at all. HIIT has been proven to have the same benefits as continuous moderate exercise (lower blood pressure, reduces body fat percentage, increase VO2 max, reduces the risk of strokes, and reduces the chances of cardiovascular diseases). Furthermore, HIIT has been shown to reduce subcutaneous fat, especially abdominal fat, as well as total body mass and improve VO2max and insulin sensitivity. The obvious advantages to HIIT are that these benefits are seen after less workout time when compared to steady state exercise.
This method of training comes in various time parameters and became more mainstream after Dr Mike Mosley looked at the subject on Horizon: The Truth About Exercise in 2012. The idea is that you exercise at a high intensity for a short period of time, at above 85% your maximal oxygen uptake, recover and then repeat. Results have been reported with only exercising for minutes a week – this does not take into account the warm up, cool down and recovery between each interval. So realistically you are looking at 20 minutes for three sessions a week. Therefore, as time is always used as an excuse not to train, this is perfect for losing fat if you’re super busy. It can work out as less time than an episode of Eastenders, and less time than doing hundreds of crunches.
The intensity of above 85%-95% maximal oxygen uptake is based on you as an individual, and based on your current fitness level. The crucial factor is to reach the target of 85% or above for your maximal oxygen uptake, which can be easily reached walking up a hill, jogging or sprinting depending on our starting level of fitness.
When we compare several academic studies of HIIT, based on 8 seconds of sprinting, followed by 12 seconds of recovery (totalling 20 minutes), aimed to reduce body fat we see that:
- Heydari et al. (2012) report abdominal fat was reduced by 6.6% and trunk fat by 8.4% in males
- Trap et al. (2008) report a decrease of 10% in both subcutaneous fat and trunk fat in females
- Vispute et al. (2011) report a 1% in spot reduction
*One must take into account that in Heydari et al. (2012) study they had a control group and no steady state group to compare against obviously exercise would work better for losing body fat when compared to a control group.
Set yourself a realistic target based on your fitness level and target an activity and intensity that allows your heart rate to reach the target of 90% max heart rate. A basic equation of this is:
220-age x 0.9 = your minimum target heart rate and 220-age x 0.95 = your max heart rate; which will take you to around 85% of you maximal oxygen uptake. I find these sessions are best done on a stationary bike, treadmill, or sprints outside/up a hill. With the bike I start on a base level, and then increase the levels as the sprint goes on. I generally stick to 30 seconds on, and 30 – 90 seconds recovery depending on the fitness of the individual. Each sprint should be at 85% or above, and the pace should feel incredibly tough as you get to the end of the interval. If it doesn’t feel hard enough, fine tune it for the next session. You want to avoid staying the same pace through each sprint – each should feel harder than the last.
Remember to train smart, making your effort and time worthwhile.
Boutcher, S. H. (2011). High-intensity intermittent exercise and fat loss. Journal of Obesity.
Heydari M., Freund, J. and Boutcher, S. H. (2012). The effect of high-intensity intermittent exercise on body composition of overweight young males. Journal of obesity.
Katch, F. I., Clarkson, P. M., Kroll, W., McBride, T. and Wilcox, A. (1984). Effects of sit up exercise training on adipose cell size and adiposity. Research Quarterly of Exercise and Sport. 55 (3), 242-247.
Ramirez-Campillo, R., Andrade, D. C., Campos-Jara, C., Henriquez-Olguin, C., Alvarez-Lepin, C. and Izquierdo, M. (2013). Regional fat changes induced by localised muscle endurance resistance training. Journal Strength and Conditioning Research. 27(8), p.2219-2224.
Trapp, E.G., Chisholm, D. J., Freund, J. And Boutcher, S. H. (2008). The effects of high-intensity intermittent exercise training on fat loss and fasting insulin levels of young women. International journal of obesity. 32, p.684-691.
Vispute, S. S., Smith, J. D., LeCheminant, J. D. and Hurley, K.S. (2011). The effect of abdominal exercise on abdominal fat. Journal of Strength and Research. 25 (9); p. 2559-2564.
Feature Photo Credit: Small by Flickr user Phil Gradwell, adapted and used under a Creative Commons