THE TEST
In the study, 24 athletes (see understanding the test) were matched based on hamstring strength into groups and allocated to one of the nutritional supplements: water, a leading isotonic sports drink or For Goodness Shakes! On each of the three days of the test the athletes completed a warm-up and before the initial measurement of height and weight. On each of the 3 test days a blood sample was taken and then the athletes completed some muscle performance measures.

On day one only following this they then completed a hamstring muscle damaging exercise on a Cybex machine. The athlete was trying to resist the machine pulling his leg straight using on his hamstring muscles. Upon completion of the exercise they immediately consumed 500ml of their allocated nutritional supplement (water, a leading isotonic sports drink or For Goodness Shakes) and a second within 2 hours.

The athletes then returned 24 and 48 hours later to have blood samples collected and completed the muscle performance measure again.

An athlete on the Cybex machine during testing

UNDERSTANDING THE TEST
We've been asked is 24 athletes a good sample size for a sports clinical trial? It is actually a fairly large sample size for a sports clinical trial. This is due to the nature of sports clinical trials. The athletes have to commit a lot of time, as well as undergo some very rigorous intense exercise, in this case muscle damaging exercise as well as invasive measurement including have blood taken, so 24 is a strong number of athletes. Other clinical trials that have been published have used significantly less athletes, Lucozade's 33% claim used 9 recreational football players. Other published trials have used: 7, 11, 7, 10, 6, 9, 15; by comparison 24 is significantly more robust as a sample size.

The 24 athletes were healthy male participants (age 21 ± 3 years; height 180.8 ± 5.7 cm; mass 80.2 ± 9.1kg) who regularly competed in team sports (football, rugby, hockey and cricket) and volunteered to take part in the study. Before beginning the study institutional ethical approval was obtained, the experimental procedures, associated risks, and benefits were explained before each participant gave their written informed consent. Participants were fully familiarized with all testing procedures prior to commencing the study. Participants were instructed to maintain their habitual diet throughout and arrive at the laboratory in a rested state, having avoided strenuous physical activity for at least 48 h and not taken any nutritional supplements, caffeine, alcohol, or anti-inflammatory drugs.

The Results >