Carbon " Super Spikes " Performances on Sprint Acceleration : Just Use it? A Multiple N-of-1 Trial. A Multiple N-of-1 Trial in Healthy Athletes

Setting. The medical commission of the Var Athletics Committee (VAC), composed by medicine doctors, physiotherapists, universitary sport-scientists and FFA coaches, was in charge of the project, at Toulon conurbation and Draguignan, France.

Design. N-of-1 Trials is the usual term for randomized, double-blind SCEDs. This one has been designed as an Alternating Treatment Design (ATD), one of the four SCEDs types 25.

Due to the strict " on-off " intervention effect, no potential interference was expected between phases, and a " best treatment " final phase seems not necessary in the absence of carry-over or interaction effects. After discussion with coaches and athletes, the main constraint was to respect a single day " standard " short-sprint training session (i.e commonly 5 to 15 repetitions, up to 500m total volume). Respecting these conditions and the preference of athletes, ATD method seemed the more appropriate, allowing the most cycle comparisons in the same time span.

Procedure. For each participants, sixteen repetitions (2 sets of 8) of maximal 30m-sprint are applied, on the same track, either with " carbon super-spikes " (CS) or standard spikes (SS), in random order for each repetition, during a 3h total session a day. Repetitions are preceded by a full warm-up, and followed by a cool-down phase. Rest time between sets and repetitions is standardised (20 and 8-10 minutes).

Block starting can't be choosen in order to limit bias (reaction time, adjustment...) and to allow radar records at the pelvis height (1-m high), as recommended, so that a split-stance starting position was adopted, without any starter (" as soon as ready ").