Losing to win - is it worth the weight?
Issue: Volume 27 Number 3
Will losing a few kilos always improve an athlete’s performance? Can it be detrimental?
For most people, weight loss is all about looking and feeling better, but for athletes it can be about improving performance, making a certain weight category (boxers or jockeys) or achieving a more aesthetic physique (body building or diving).
Athletes often feel substantial pressure to conform to a body weight or fat ideal of their sport, but there is generally a range of weight and body fat levels considered optimal (Kerr and Ackland 2000). Fortunately, in most sports this range is reasonably wide, for example football, tennis, cricket, while in other sports such as gymnastics and figure skating the range is narrow. Unfortunately, this means athletes may struggle to meet weight and body fat expectations imposed by the sport or even themselves.
Does weight or fat loss benefit athletic performance?
Scientific evidence and common sense both support the need to be light and lean in endurance sports like marathon running or triathlon, where body weight must be carried over a significant distance (Tittel 1987). Low body weight decreases the energy cost of moving and improves body temperature control, especially when exercising in hot, humid weather(Cureton and Sparling 1980).
In other sports such as football, sprinting and jumping, a more substantial muscle mass is required for strength, so the ratio of muscle mass to fat is more important (Malina 1975).
Surprisingly, there is little published research specifically investigating the effect of body weight or fat on performance. Many of the optimal ranges suggested come from measures taken on elite performers or from a coach's intuition or experience. While these ranges are a guide, they do not account for an athlete's individuality (O'Connor, Sullivan and Caterson 2000). Many Australian athletes have excelled with physiques that didn't fit into the 'ideal range' for their sport. Look at Tony Lockett in AFL and sprinter Melinda Gainsford-Taylor.
The decision to reduce body weight rests largely on how that athlete's physique compares with the accepted ranges for their sport. But, while a reduction in body fat may help a long distance runner, it may have less benefit for a shot putter. In fact, body fat may be beneficial in contact sports as it cushions bones and organs (Brewer and Davis 1995). Fat may also aid buoyancy for swimmers, but excess fat may increase drag in the water (Stager and Cordain 1984).
Athletes most likely to benefit from body fat loss are those involved in:
- Sports with significant running or jumping
- Sports competed in hot/humid environments
- Aesthetic sports
- Weight-class sports .
Genetics and body weight
Not everyone can design and then achieve a specific level of body weight or body fat (Boucher). Genetics plays a big role.
Some athletes can maintain an optimal weight easily; others can find it very hard. Struggling athletes may resort to drastic and unsound dietary practices, which sooner or later have a negative impact on their health, performance and mental state. Genetics ultimately influence an athlete’s ability to successfully and safely achieve and maintain desirable levels of body weight or body fat.
Determining goals
Body weight and body fat goals should be based on the sport and position, current and past body composition, and time remaining until competition.
Some athletes, in their desire to achieve their goal, over-restrict their intake or try inappropriate fad diets. Unfortunately, this behaviour often delivers a short-term weight loss, but it is composed mainly of water and lean tissue. They weigh less on the scales, but they barely manage to complete training sessions and can’t recover properly.
If weight or fat loss becomes a serious issue for an athlete, a sports dietitian should be consulted.
Weight loss in a child athlete needs to be carefully assessed and carried out gradually to ensure optimal nutrition and maintenance of growth.
Some strategies for coaches and athletes attempting to lose body fat:
• Create an energy deficit - The most effective way to lose body fat, usually measured by skin folds, is by eating a little less energy (kilojoules or calories) than is burnt, to create a slight energy deficit or negative energy balance.
• Ask your athletes - What high fat foods are you consuming regularly that you could do without? Are you regularly drinking too much alcohol? Are you eating the right type of food, low fat and high carbohydrate, or are you eating too much? Have you got the quantities of different foods right for you?
• Keep a food record - This is a useful way to increase awareness of when, where and what is being consumed.
• Any ‘triggers’ to overeating? - Eating is closely linked to emotions. Athletes use food at times to calm themselves or deal with stress, injury or boredom.
• Forget the diet - ‘Dieting’ sets up athletes to feel deprived and think about all those foods they can’t eat! They are setting themselves up to eventually overeat or binge.
• Plan low-fat, high carbohydrate meals and snacks ahead of time - Serious athletes should plan their meals and snacks. When an athlete is hungry and has no healthy food at home they often resort to fast foods or high fat snack foods.
• Be realistic - Do they really need to achieve that weight or skin fold?
Practical Tips for CoachesAchieving desired levels of body weight or body fat may improve performance in some, but not all, athletes. Before an athlete embarks on a weight or fat loss program consider the following:
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References
Kerr D and T Ackland. Kinanthropometry: physique assessment of the athlete. In Clinical Sports Nutrition 2nd edition, Burke L, Deakin V. (Ed.). Sydney: McGraw Hill, pp 69-89, 2000.
Tittel K. Tasks and tendencies of sport anthropometry's development. In Biomechanics of sport and kinanthropometry, Landry F and Orban WA (Ed.). Miami: Symposia Specialists, pp 283-296, 1978.
Cureton KJ and PB Sparling. Distance running performance and metabolic responses to running in men and women with excess weight experimentally equated. Med Sci Sport Exerc 1980;12(4):288-294.
Malina RM. Anthropometric correlates of strength and motor performance. Ex Sport Sci Rev 1975;3:249-274.
O'Connor H, Sullivan T, and I Caterson. Weight loss and the athlete. In Clinical Sports Nutrition 2nd edition, Burke L, Deakin V. (Ed.). Sydney: McGraw Hill, pp 146-184, 2000.
Brewer J and J Davis. Applied physiology of rugby league. Sports Med 1995;20(3):129-135.
Stager JM and L Cordain. Relationship of body composition to swimming performance in female swimmers. J Swim Res 1984;1:21-24.
Bouchard C. Genetics of Obesity: overview and research directions. In The Genetics of Obesity, Bouchard C. (Ed.). Boca Raton: CRC Press, pp 223-233, 1994.
Acknowledgements
This article is reproduced with the permission of the editorial team at Coaches' Edge, author Dr Deborah Kerry, Senior Lecturer at Curtin University WA, and Sports Dietitians Australia. To join the Coaches' Edge log onto www.coachesedge.com.au.
