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Weight: The Percentage Factor


Mention diet within the confines of athletics and you can occasionally expect to have the politically correct brigade bring out the usual buzz word of ‘anorexia’ - especially if the athlete is a woman, which at times can be tiring.  Coaches responsible for the preparation and performance of elite athletes are well aware of the implications of a dietary regime on a committed athlete.

There is no doubt that the single most effective way to improve performance - in the short term - is loss of weight, if of course there is an excess of body fat.  It is this factor alone that is central to the issue when discussing weight loss - and not the overall weight of the athlete.

The only problem - in my experience – has been when restrictive diets have been undertaken by juniors under 18-20 years of age, when their bodies are still growing.  This is a more delicate area and only professional dieticians should have a say within this age group.

Commonsense must always prevail when discussing weight reduction for any athlete who is on a demanding training regime, if an athlete is to maximize their performance it is essential that they adopt a sensible approach to a healthy-eating regime as part of an overall training package.

So how can an athlete determine if they are a case for weight loss based on fat percentage?

Unfortunately people cannot tell by simply weighing themselves and looking at a height-weight chart what their % body fat is, or if they are overweight or underweight.  Height-weight charts are based on averages, and only about 20% of the population conforms to the averages on the charts.  The charts make no allowance for muscle development, and most people don’t really know what their frame size is.  The only way to determine the amount of fat on an athlete’s body is by actual measurement of their body fat.

A normal healthy person – not athlete - should fall within the following bands of fat percentage:

For men up to about age 30, 9 – 15% is good.  From age 30–50, 11 to 17% is a good range, and from age 50 and up, 12 – 19% is about right.

For women, the range up to age 30 is 14 to 21%, from 30-50, 15 to 23% and from 50 up it is 16 to 25%.

The reason I say for a normal healthy person, is that athletes vary appreciably from these figures and depending on what level the athlete is at will vary even more.  The various disciplines within athletics allow for more variation, and not always lower!  Olympic throwers usually come in around the 30% mark, whereas Olympic swimmers can be in the 9–12% band.  Rowers who work from a power base can hover around the 15% mark, whereas the running disciplines start to plunge with elite male marathon and middle distance runners, dipping below the 5% figure.

So the variation is tremendous and it calls for expert advice on where each individual athlete should be, at that moment of time in their career, taking into account age, sex, ability and sport discipline.

Measuring body fat also has its variations.  The most accurate way is obtained by underwater weighing, but considering the equipment required, only a few Universities and the like have this facility.  Most coaches and health professionals use the Skin Fold Caliper method which is very accurate.  Body Fat Monitors (BFM) are becoming increasingly popular but come in at around £100 for a good set of scales.  The more you pay the more accurate they become.

If you don’t want to be too precise then the BMI method is fine, just follow the formula at the end of this article and see where you fit in.  This method does not take into account those larger athletes who are very fit; rugby players, weight lifters, etc.

Finally if you are ace with a calculator you could always try the Stillman Table, a tried and tested formula for checking your height/weight ratio.

It is worked on the average man principle:

The average man is allocated 110 lbs (50 kg) for the first 5 feet (1.524 m) in height.  Thereafter, he is allocated 5½ lbs (2.495 kg) for every additional inch (0.025 m) in height.

Thus, a man 6 feet tall (1.829 m) would be allocated 110 lbs (50 kg) plus 12 x 5½ lbs (2.495 kg), which comes to 176 lbs or 12 st. 8 lbs (80 kg).

Females are allocated 100 lbs (45 kg) for the first 5 feet (1.524 m) and 5lbs (2.268 kg) for every inch thereafter.  Therefore a woman who is 5 ft 6 ins (1.676 m) tall would be given 100 lbs plus 6 x 5 lbs, which totals 130 lbs or 9 st. 4 lbs (59 kg).

These figures are based on calculations for healthy non-active people, and athletes who run middle-distance (800m - 10K) need to be around 12 per cent lighter.  Longer distance runners (10 miles onwards) need to be looking at being 15 per cent lighter.

So if all that confuses you then simply go and see your club coach and see if he will do a fat percentage check.  Having established a percentage figure, what you do with it is a whole new ball game, and for another article.

Norman Matthews


BMI = (

Weight in lbs


) x 7.03
(Height in inches) x (Height in inches)

Or you can forget the calculations and use the pre-set tables below; sorry it’s in old money!  But considering that vets rule on race numbers I am all for democracy.

Body weight in pounds according to height and body mass index.

 

BMI
(kg/m2)

19

20

21

22

23

24

25

26

27

28

29

30

35

40

Height
(in.)

Weight (lb.)

58

91

96

100

105

110

115

119

124

129

134

138

143

167

191

59

94

99

104

109

114

119

124

128

133

138

143

148

173

198

60

97

102

107

112

118

123

128

133

138

143

148

153

179

204

61

100

106

111

116

122

127

132

137

143

148

153

158

185

211

62

104

109

115

120

126

131

136

142

147

153

158

164

191

218

63

107

113

118

124

130

135

141

146

152

158

163

169

197

225

64

110

116

122

128

134

140

145

151

157

163

169

174

204

232

65

114

120

126

132

138

144

150

156

162

168

174

180

210

240

66

118

124

130

136

142

148

155

161

167

173

179

186

216

247

67

121

127

134

140

146

153

159

166

172

178

185

191

223

255

68

125

131

138

144

151

158

164

171

177

184

190

197

230

262

69

128

135

142

149

155

162

169

176

182

189

196

203

236

270

70

132

139

146

153

160

167

174

181

188

195

202

207

243

278

71

136

143

150

157

165

172

179

186

193

200

208

215

250

286

72

140

147

154

162

169

177

184

191

199

206

213

221

258

294

73

144

151

159

166

174

182

189

197

204

212

219

227

265

302

74

148

155

163

171

179

186

194

202

210

218

225

233

272

311

75

152

160

168

176

184

192

200

208

216

224

232

240

279

319

76

156

164

172

180

189

197

205

213

221

230

238

246

287

328

 

BMI

18.5 or lessUnderweight
18.5 - 24.9Normal
25.0 - 29.9Overweight
30.0 - 34.9Obese
35.0 - 39.9Obese
40 or greaterExtremely Obese


Norman Matthews © 2001-2004
Head Senior Coach
Horwich RMI Harriers