Background
Methods
Participants
Study design
Supplement Category | Individual Supplements Listed |
---|---|
Dietary/Medical | Multi-vitamin/Multi-mineral Vitamin C B-Vitamins Vitamin D Vitamin E Vitamin-enriched water Calcium Iron Magnesium |
Other Supplements | Fatty acid preparations Plant/herbal extracts |
Ergogenic Aids (Muscle Building/Increased Energy) | Branched chain amino acids Beta-alanine Glutamine Creatine Energy drinks |
Performance Foods | Protein powder Sport/electrolyte drinks Recovery drinks Protein/sport bar Sport gels Gummy/bean |
Reason Category | Individual Reasons Listed |
---|---|
Health-Related | Medical (your doctor told you to) To improve your diet (food you eat everyday) Stay healthy Enhance immune system (so you don’t get sick) |
Performance-Related | Increase or maintain muscle mass, strength, and/or power Increase endurance (how long you can exercise) Increase energy (so you don’t feel tired) Enhance overall athletic performance Improve exercise recovery (after exercise) |
Influence of Others | Because others (friends, family, teammates) do Someone told you to (coach, parent, friend etc.) |
Criteria for evaluating outcome measures
Statistical analyses
Results
Self-evaluation of knowledge for reasons for supplementation
Supplement choice and health related reasons
Supplement | Medical (19 %) | Improve Diet (43 %) | Stay Healthy (81 %) | Support Immune System (52 %) |
---|---|---|---|---|
Multi-vitamin/Multi-mineral (67 %) |
χ
2
= 12.576
p
< 0.001
V = 0.150
|
χ
2 = 7.057
p = 0.008 V = 0.112 |
χ
2
= 32.679
p
< 0.001
V = 0.241
|
χ
2
= 41.807
p
< 0.001
V = 0.273
|
Vitamin C (66 %) |
χ
2 = 5.825
p = 0.016 V = 0.102 |
χ
2
= 15.603
p
< 0.001
V = 0.166
|
χ
2
= 35.707
p
< 0.001
V = 0.252
|
χ
2
= 32.878
p
< 0.001
V = 0.241
|
B Vitamins (32 %) |
χ
2 = 3.623
p = 0.057 V = 0.080 |
χ
2
= 12.740
p
< 0.001
V = 0.150
|
χ
2
= 14.195
p
< 0.001
V = 0.159
|
χ
2
= 17.709
p
< 0.001
V = 0.177
|
Vitamin E (26 %) |
χ
2 = 2.136
p = 0.144 V = 0.062 |
χ
2 = 8.109
p = 0.004 V = 0.120 |
χ
2 = 8.428
p = 0.004 V = 0.122 |
χ
2
= 10.368
p
= 0.001
V = 0.136
|
Vitamin D (48 %) |
χ
2
= 15.691
p
< 0.001
V = 0.167
|
χ
2
= 12.615
p
< 0.001
V = 0.150
|
χ
2
= 32.496
p
< 0.001
V = 0.240
|
χ
2
= 22.208
p
< 0.001
V = 0.199
|
Vitamin-enriched Water (65 %) |
χ
2 = 3.386
p = 0.066 V = 0.077 |
χ
2 = 4.664
p = 0.031 V = 0.091 |
χ
2 = 5.183
p = 0.023 V = 0.096 |
χ
2 = 2.510
p = 0.113 V = 0.067 |
Iron (27 %) |
χ
2
= 17.142
p
< 0.001
V = 0.174
|
χ
2
= 20.320
p
< 0.001
V = 0.190
|
χ
2
= 13.759
p
< 0.001
V = 0.156
|
χ
2
= 16.803
p
< 0.001
V = 0.172
|
Calcium (43 %) |
χ
2
= 22.947
p
< 0.001
V = 0.202
|
χ
2
= 30.458
p
< 0.001
V = 0.232
|
χ
2
= 31.370
p
< 0.001
V = 0.236
|
χ
2
= 26.782
p
< 0.001
V = 0.218
|
Magnesium (17 %) |
χ
2 = 1.001
p = 0.317 V = 0.042 |
χ
2 = 9.440
p = 0.002 V = 0.129 |
χ
2 = 8.538
p = 0.003 V = 0.123 |
χ
2
= 12.815
p
< 0.001
V = 0.151
|
Protein Powder (51 %) |
χ
2 = 1.692
p = 0.193 V = 0.055 |
χ
2
= 14.825
p
< 0.001
V = 0.162
|
χ
2 = 5.085
p = 0.024 V = 0.095 |
χ
2
= 16.882
p
< 0.001
V = 0.173
|
BCAA (8 %) |
χ
2 = 0.233
p = 0.629 V = 0.020 |
χ
2 = 9.765
p = 0.002 V = 0.132 |
χ
2 = 2.415
p = 0.120 V = 0.065 |
χ
2 = 7.317
p = 0.007 V = 0.114 |
Beta-alanine (4 %) |
χ
2 = 5.191
p = 0.023 V = 0.096 |
χ
2 = 3.369
p = 0.066 V = 0.077 |
χ
2 = 0.871
p = 0.351 V = 0.039 |
χ
2 = 0.228
p = 0.633 V = 0.020 |
Glutamine (8 %) |
χ
2 = 0.260
p = 0.610 V = 0.021 |
χ
2
= 13.015
p
< 0.001
V= 0.152
|
χ
2 = 4.687
p = 0.030 V = 0.091 |
χ
2 = 6.923
p = 0.009 V = 0.111 |
Fatty Acids (40 %) |
χ
2
= 13.960
p
< 0.001
V = 0.157
|
χ
2 = 9.602
p = 0.002 V = 0.130 |
χ
2
= 21.589
p
< 0.001
V = 0.196
|
χ
2
= 34.971
p
< 0.001
V = 0.249
|
Energy Drinks (27 %) |
χ
2 = 4.642
p = 0.031 V = 0.091 |
χ
2 = 8.362
p = 0.004 V = 0.122 |
χ
2 = 0.757
p = 0.384 V = 0.037 |
χ
2 = 0.285
p = 0.593 V = 0.022 |
Sport/Electrolyte Drinks (90 %) |
χ
2 = 0.817
p = 0.366 V = 0.038 |
χ
2 = 1.164
p = 0.281 V = 0.045 |
χ
2 = 5.081
p = 0.024 V = 0.095 |
χ
2 = 1.172
p = 0.279 V = 0.046 |
Sport Gels/Gummies (26 %) |
χ
2 = 1.315
p = 0.251 V = 0.048 |
χ
2 = 0.555
p = 0.456 V = 0.031 |
χ
2 = 5.810
p = 0.016 V = 0.101 |
χ
2 = 3.462
p = 0.063 V = 0.078 |
Sport/Protein Bar (71 %) |
χ
2 = 0.961
p = 0.327 V = 0.041 |
χ
2
= 10.708
p
= 0.001
V = 0.138
|
χ
2
= 11.233
p
= 0.001
V = 0.141
|
χ
2
= 10.456
p
= 0.001
V = 0.136
|
Recovery Drinks (31 %) |
χ
2 = 0.166
p = 0.684 V = 0.017 |
χ
2
= 10.532
p
= 0.001
V = 0.137
|
χ
2 = 6.735
p = 0.009 V = 0.109 |
χ
2 = 9.528
p = 0.002 V = 0.130 |
Creatine (7 %) |
χ
2 = 0.015
p = 0.903 V = 0.005 |
χ
2 = 1.416
p = 0.234 V = 0.050 |
χ
2 = 0.123
p = 0.726 V = 0.015 |
χ
2 = 1.617
p = 0.204 V = 0.054 |
Plant Extracts (47 %) |
χ
2 = 9.536
p = 0.002 V = 0.130 |
χ
2 = 7.859
p = 0.005 V = 0.118 |
χ
2 = 9.864
p = 0.002 V = 0.132 |
χ
2
= 49.130
p
< 0.001
V = 0.295
|
Supplement choice and performance related reasons
Supplement | Muscle Mass/Strength (38 %) | Endurance (31 %) | Increase Energy (55 %) | Overall Athletic Performance (49 %) | Recovery (49 %) |
---|---|---|---|---|---|
Multi-vitamin/Multi-mineral (67 %) |
χ
2
= 11.965
p
= 0.001
V = 0.146
|
χ
2 = 8.469
p = 0.004 V = 0.123 |
χ
2 = 0.203
p = 0.652 V = 0.019 |
χ
2 = 6.370
p = 0.012 V = 0.106 |
χ
2 = 5.773
p = 0.016 V = 0.101 |
Vitamin C (66 %) |
χ
2 = 7.688
p = 0.006 V = 0.117 |
χ
2 = 5.278
p = 0.022 V = 0.097 |
χ
2 = 2.580
p = 0.108 V = 0.068 |
χ
2 = 4.662
p = 0.031 V = 0.091 |
χ
2 = 3.046 p = 0.081 V = 0.073 |
B Vitamins (32 %) |
χ
2
= 11.002
p
= 0.001
V = 0.140
|
χ
2
= 20.610
p
< 0.001
V = 0.191
|
χ
2 = 6.675
p = 0.010 V = 0.109 |
χ
2
= 11.867
p
= 0.001
V = 0.145
|
χ
2 = 1.487
p = 0.223 V = 0.051 |
Vitamin E (26 %) |
χ
2
= 25.084
p
< 0.001
V = 0.211
|
χ
2
= 27.410
p
< 0.001
V = 0.221
|
χ
2
= 10.883
p
= 0.001
V = 0.139
|
χ
2
= 18.510
p
< 0.001
V = 0.181
|
χ
2 = 2.257
p = 0.133 V = 0.063 |
Vitamin D (48 %) |
χ
2 = 9.013
p = 0.003 V = 0.127 |
χ
2
= 12.488
p
< 0.001
V = 0.149
|
χ
2 = 0.619
p = 0.431 V = 0.033 |
χ
2 = 2.629
p = 0.105 V = 0.068 |
χ
2 = 0.616
p = 0.433 V = 0.033 |
Vitamin- enriched Water (65 %) |
χ
2 = 5.594
p = 0.018 V = 0.100 |
χ
2
= 10.919
p
= 0.001
V = 0.139
|
χ
2
= 13.372
p
< 0.001
V = 0.154
|
χ
2
= 17.511
p
< 0.001
V = 0.176
|
χ
2 = 4.535
p = 0.033 V = 0.090 |
Iron (27 %) |
χ
2 = 6.234
p = 0.013 V = 0.105 |
χ
2 = 7.387
p = 0.007 V = 0.114 |
χ
2 = 6.574
p = 0.010 V = 0.108 |
χ
2 = 7.795
p = 0.005 V = 0.117 |
χ
2 = 0.223
p = 0.637 V = 0.020 |
Calcium (43 %) |
χ
2
= 25.438
p
< 0.001
V = 0.212
|
χ
2
= 10.571
p
= 0.001
V = 0.137
|
χ
2 = 9.816
p = 0.002 V = 0.132 |
χ
2
= 10.204
p
= 0.001
V = 0.134
|
χ
2 = 3.097
p = 0.078 V = 0.074 |
Magnesium (17 %) |
χ
2
= 11.060
p
= 0.001
V = 0.140
|
χ
2
= 16.037
p
< 0.001
V = 0.169
|
χ
2 = 7.193
p = 0.007 V = 0.113 |
χ
2 = 7.827
p = 0.005 V = 0.118 |
χ
2 = 5.510
p = 0.019 V = 0.099 |
Protein Powder (51 %) |
χ
2
= 120.609
p
< 0.001
V = 0.462
|
χ
2
= 27.927
p
< 0.001
V = 0.223
|
χ
2
= 12.172
p
< 0.001
V = 0.147
|
χ
2
= 47.946
p
< 0.001
V = 0.292
|
χ
2
= 51.470
p
< 0.001
V = 0.302
|
BCAA (8 %) |
χ
2
= 21.995
p
< 0.001
V = 0.198
|
χ
2
= 14.313
p
< 0.001
V = 0.159
|
χ
2 = 7.943
p = 0.005 V = 0.119 |
χ
2
= 16.010
p
< 0.001
V = 0.169
|
χ
2 = 3.392
p = 0.065 V = 0.078 |
Beta-alanine (4 %) |
χ
2 = 3.440
p = 0.064 V = 0.078 |
χ
2 = 5.451
p = 0.020 V = 0.098 |
χ
2 = 3.095
p = 0.079 V = 0.074 |
χ
2 = 2.462
p = 0.117 V = 0.066 |
χ
2 = 0.536
p = 0.464 V = 0.031 |
Glutamine (8 %) |
χ
2
= 26.895
p
< 0.001
V = 0.218
|
χ
2
= 27.131
p
< 0.001
V = 0.219
|
χ
2 = 9.594
p = 0.002 V = 0.130 |
χ
2
= 15.530
p
< 0.001
V = 0.166
|
χ
2
= 15.335
p
< 0.001
V = 0.165
|
Fatty Acids (40 %) |
χ
2
= 12.534
p
< 0.001
V = 0.149
|
χ
2 = 4.866
p = 0.027 V = 0.093 |
χ
2 = 0.302
p = 0.583 V = 0.023 |
χ
2 = 2.087
p = 0.149 V = 0.061 |
χ
2 = 0.267
p = 0.606 V = 0.022 |
Energy Drinks (27 %) |
χ
2
= 14.246
p
< 0.001
V = 0.159
|
χ
2 = 5.024
p = 0.025 V = 0.094 |
χ
2
= 22.360
p
< 0.001
V = 0.199
|
χ
2 = 0.653
p = 0.419 V = 0.034 |
χ
2 = 4.312
p = 0.038 V = 0.087 |
Sport/Electrolyte Drinks (90 %) |
χ
2
= 17.637
p
< 0.001
V = 0.177
|
χ
2 = 9.922
p = 0.002 V = 0.133 |
χ
2
= 19.795
p
< 0.001
V = 0.187
|
χ
2
= 16.349
p
< 0.001
V = 0.170
|
χ
2
= 18.945
p
< 0.001
V = 0.183
|
Sport Gels/Gummies (26 %) |
χ
2
= 14.132
p
< 0.001
V = 0.158
|
χ
2 = 8.300
p = 0.004 V = 0.121 |
χ
2
= 12.120
p
< 0.001
V = 0.146
|
χ
2 = 8.098
p = 0.004 V = 0.120 |
χ
2
= 18.349
p
< 0.001
V = 0.180
|
Sport/Protein Bar (71 %) |
χ
2
= 27.780
p
< 0.001
V = 0.222
|
χ
2
= 29.989
p
< 0.001
V = 0.230
|
χ
2
= 16.794
p
< 0.001
V = 0.172
|
χ
2
= 28.890
p
< 0.001
V = 0.226
|
χ
2
= 38.043
p
< 0.001
V = 0.259
|
Recovery Drinks (31 %) |
χ
2
= 57.268
p
< 0.001
V = 0.319
|
χ
2
= 41.358
p
< 0.001
V = 0.271
|
χ
2
= 16.384
p
< 0.001
V = 0.171
|
χ
2
= 41.349
p
< 0.001
V = 0.271
|
χ
2
= 61.395
p
< 0.001
V = 0.330
|
Creatine (7 %) |
χ
2
= 19.434
p
< 0.001
V = 0.186
|
χ
2
= 15.634
p
< 0.001
V = 0.166
|
χ
2 = 3.173
p = 0.075 V = 0.075 |
χ
2
= 10.546
p
< 0.001
V = 0.137
|
χ
2 = 6.629
p = 0.010 V = 0.108 |
Plant Extracts (47 %) |
χ
2 = 8.426
p = 0.004 V = 0.122 |
χ
2 = 2.079
p = 0.149 V = 0.061 |
χ
2 = 7.471
p = 0.006 V = 0.115 |
χ
2 = 5.633
p = 0.018 V = 0.100 |
χ
2 = 3.194
p = 0.074 V = 0.075 |
Supplement choice and influence of others
Supplement | Family/Friends/Teammates (21 %) | Someone Told You To (35 %) |
---|---|---|
Multi-vitamin/Multi-mineral (67 %) |
χ
2 = 1.074
p = 0.300 V = 0.044 |
χ
2
= 15.358
p
< 0.001
V = 0.165
|
Vitamin C (66 %) |
χ
2 = 0.522
p = 0.470 V = 0.030 |
χ
2 = 1.273
p = 0.259 V = 0.048 |
B Vitamins (32 %) |
χ
2 = 2.480
p = 0.115 V = 0.066 |
χ
2 = 1.255
p = 0.263 V = 0.047 |
Vitamin E (26 %) |
χ
2 = 1.070
p = 0.301 V = 0.044 |
χ
2 = 2.727
p = 0.099 V = 0.070 |
Vitamin D (48 %) |
χ
2 = 0.014
p = 0.904 V = 0.005 |
χ
2 = 9.449
p = 0.002 V = 0.130 |
Vitamin-enriched Water (65 %) |
χ
2 = 2.108
p = 0.147 V = 0.061 |
χ
2 = 0.195
p = 0.659 V = 0.019 |
Iron (27 %) |
χ
2 = 2.982
p = 0.084 V = 0.073 |
χ
2 = 4.773
p = 0.029 V = 0.092 |
Calcium (43 %) |
χ
2 = 6.104
p = 0.013 V = 0.104 |
χ
2 = 7.059
p = 0.008 V = 0.112 |
Magnesium (17 %) |
χ
2 = 3.587
p = 0.058 V = 0.080 |
χ
2 = 1.846
p = 0.174 V = 0.057 |
Protein Powder (51 %) |
χ
2 = 0.005
p = 0.941 V = 0.003 |
χ
2 = 0.003
p = 0.959 V = 0.002 |
BCAA (8 %) |
χ
2 = 0.051
p = 0.821 V = 0.010 |
χ
2 = 0.031
p = 0.859 V = 0.007 |
Beta-alanine (4 %) |
χ
2 = 0.003
p = 0.957 V = 0.002 |
χ
2 = 0.012
p = 0.914 V = 0.005 |
Glutamine (8 %) |
χ
2 = 1.393
p = 0.238 V = 0.050 |
χ
2 = 0.289
p = 0.591 V = 0.023 |
Fatty Acids (40 %) |
χ
2 = 2.852
p = 0.091 V = 0.071 |
χ
2 = 7.947
p = 0.005 V = 0.119 |
Energy Drinks (27 %) |
χ
2 = 3.643
p = 0.056 V = 0.080 |
χ
2 = 5.330
P = 0.021 V = 0.097 |
Sport/Electrolyte Drinks (90 %) |
χ
2 = 5.129
p = 0.024 V = 0.095 |
χ
2 = 0.165
p = 0.685 V = 0.017 |
Sport Gels/Gummies (26 %) |
χ
2 = 6.952
p = 0.008 V = 0.111 |
χ
2 = 0.882
p = 0.348 V = 0.039 |
Sport/Protein Bar (71 %) |
χ
2 = 6.420
p = 0.011 V = 0.107 |
χ
2 = 3.154
p = 0.076 V = 0.075 |
Recovery Drinks (31 %) |
χ
2 = 0.049
p = 0.826 V = 0.009 |
χ
2 = 0.365
p = 0.546 V = 0.025 |
Creatine (7 %) |
χ
2 = 3.489
p = 0.062 V = 0.079 |
χ
2 = 0.012
p = 0.913 V = 0.005 |
Plant Extracts (47 %) |
χ
2 = 0.376
p = 0.540 V = 0.026 |
χ
2 = 0.412
p = 0.521 V = 0.027 |