Dear Dr Maher

Thank-you for the letter and interest in the research on compression garments we recently published in BJSM (and apologies for the delayed response – conference and holiday time!). Further, we appreciate the comments and required clarification of the specificity of the research design in relation to cricket. As with the English system, in Australia cricket matches are also conducted over both singular and multiple (consecutive) days of play. However, this is where some misunderstanding of the intention of the research project may have occurred, as it was not the intention of the authors to directly simulate game play or replicate match demands or the associated effects of compression garments on cricket matches. Rather it was the intention of the authors to determine the effects of the compression garments on performance and physiological parameters associated with upper- and lower-body intermittent-sprint exercise, as would be used by athletes in training or competition with a focus on cricket players (who use both upper and lower-body).

Currently there is no published literature on cricket match demands (although we have a manuscript in-review on the time-motion analysis of Test and One-Day International matches which is likely to be the first data published on this topic), which makes the quantification and validation of any exercise protocol attempting to replicate cricket demands difficult. Further, while the type of activity pattern used in the current exercise protocol may not specifically replicate the demands of a cricket match, it is however, generic to the type of intermittent-sprint patterns found in physical conditioning and training programs in both cricket and other repeat-sprint sports. Hence, while the exercise may not specifically replicate game demands, it does replicate the high-intensity demands of many training programs (during which compression garments are often worn). Additionally, this was also an aspect of the study that was important to us; to allow for a larger scale application of the use of compression garments to sports other than just cricket. Finally, the exercise protocol used here has previously been reported to be sensitive enough to elucidate small changes in exercise performance resulting from different interventions or conditions imposed (as reported in a paper we have published in EJAP on pre-cooling procedures: Duffield and Marino 2007). Therefore, as outlined, while the exercise protocol utilised was not specifically indicative of the demands of a cricket match, as there is currently no information on what those match demands are, combined with the greater applicability to a range of sports of a generic intermittent- sprint protocol used in training and conditioning scenarios (which is sensitive enough to detect changes in both maximal and sub-maximal performance), we feel this option best served both the cricketing and larger team-sports communities.

In response to other suggestions and comments, the 72-96 h with avoidance of exercise, food and caffeine is standard methodological research design when using any randomised, cross-over design research. Given (for the above reasons) we chose a 30-min generic intermittent- sprint exercise protocol, in order to ensure there were no effects of the exercise in one condition (garment) on the next, a sufficient ‘wash-out’ period is required to ensure any delayed soreness or elevated CK was not present in baseline measures of the next condition. Hence, again, while this may not replicate demands of consecutive day cricket, it is what is required for maintenance of research integrity. The design of the study was to determine the acute effects of compression garments on a bout of high-intensity exercise; hence the 3-4 days rest was not of relevance to the determination of effects of comparison of performance on cricket matches, however allowed a return to a resting baseline for all physiological measures in all respective conditions.

As indicated in your letter, results published in our paper reported a reduction in 24 h post-exercise CK and perceived muscle soreness which may indicate the usefulness of the garments to prepare players for training or game demands the following day (improved recovery). The suggestion to perform testing involving consecutive day exercise is a good idea; however, we have already performed similar testing in rugby players with similar results to the current study. Regardless of improved ratings of muscle soreness or reduced CK values, neither of these parameters have any direct association with performance in intermittent-sprint exercise. As such, this further research we have performed highlights this during exercise protocols that induce higher metabolic, physiological and contusion loads than would be found in cricket; however, still resulted in minimal ergogenic benefits of the garments on repeated bouts over consecutive days of exercise. Further, given the limited evidence of the role in elevated CK or perceptual measures accounting for performance changes, and little other evidence of the effect of compression garments on any other physiological functioning in healthy athletic populations, it is currently equivocal that compression garments provide performance benefit in intermittent-sprint activity. Finally, as is well stated in your e-letter, that while it may be unsurprising skin temperature was higher under the respective garments, a perusal of many compression garment web-sites will reveal that this is the opposite to how the garments are being advertised and sold (and in essence are being marketed in contradiction of normal thermoregulatory functioning of the body!).

In conclusion, while we appreciate the suggestions provided, the main idea proposed (consecutive day exercise protocol with performance measures) has already been performed, with no indication that exercise performance (speed, power, strength or aerobic ability) is improved when wearing compression garments during single or consecutive days of intermittent-sprint exercise. Further, the current study was designed as a more generic investigation using cricket players (who engage in both upper - and lower-body intermittent exercise) rather than on cricket per se.

Regards

Rob Duffield, PhD

School of Human Movement, Charles Sturt University