Interestingly, some athletes experience cramps more than others. One possible risk factor for exercise associated muscle cramping (EAMC) is actually a history of cramping itself, though the reason for that is unclear. But, the major EAMC risk factor is fatigue or competing at a higher intensity than you prepared for in training. Maybe surprisingly, dehydration and serum sodium changes do not appear to predict EAMC.
Even though athletes often take a variety of electrolyte supplements, sometimes with the intention of preventing cramps, it’s unclear how electrolytes may actually influence EAMC. When electrolyte concentration is measured in plasma, it’s unlikely that the values reflect intra- and extracellular electrolyte concentrations in muscle and nerve cells local to the area of cramping. Also, EAMC is most commonly experienced within the muscles being used and is not "system-wide". Cramping is also often associated with high rates of sweat loss during exercise in the heat, but it can also occur in cool environments with little sweat loss. These observations suggest that, while we can’t rule out the involvement of either sweat loss or electrolyte changes in EAMC, these factors don’t fully explain EAMC in general.
Ultimately, there’s no consensus on the exact cause of cramping so we can’t make clear cut recommendations for cramping prevention during training or racing. For some people, it may be that hot temperatures, high sweat losses, and ingestion of large volumes of plain water can be risk factors for cramping and that the addition of salt to fluids might help.
Pickle juice, mustard, vinegar and capsaicin shots have also been used in an attempt to prevent or alleviate cramps. All of these have some type of strong, bitter, or spicy taste and their components can activate TRP receptors (pain or taste sensors) in the mouth and gut; which, in turn stimulate the central nervous system (CNS). These TRP-stimulating components are typically found in commercially available “shots” (e.g. combo of vinegar, lime juice, cinnamon, ginger, capsaicin) marketed to help or prevent EAMC. These products and their unpleasant taste are suggested to activate the TRP-related oropharyngeal reflex via the CNS; that would, in theory, override a sustained muscle contraction/cramp.
Pickle juice (containing sodium and acetic acid), arguably the most popular, has been shown to be effective for reducing the duration of cramps by 37% when consumed immediately after the onset of cramping (induced in a lab setting by electrical stimulation). Unfortunately, because this wasn’t an exercise study, these findings can’t be directly translated to “real world” EAMC scenarios. Furthermore, ingestion of small volumes of pickle juice does not appear to affect plasma electrolyte concentrations, plasma osmolality, or plasma volume.
Commercially available capsaicin shots have been touted to provide a longer lasting effect against cramping due to the proposed TRP-induced mechanism. However, there is limited research to support these claims so far; and, interestingly, the mouth requires a local pH of <6 in order for capsaicin to activate the TRP channel. Oral pH is likely going to differ between individuals and we don’t have a good way to know the pH in our mouth when we are out riding!
Again, one big limitation when attempting this type of research is getting people to cramp on demand. Electrically-induced cramping is a different process than what is likely happening physiologically during EAMC. While there is emerging evidence to support the use of these products, more research in a field based setting (e.g. race, or training) is needed to determine whether foods with a spicy/intense taste can actually disrupt spontaneous cramping, the optimal dose, and most effective combination of compounds.
tl;dr: The best strategy against EAMC seems to be not over-racing at an intensity/pace/effort based on what we have prepared for in training, especially when environmental conditions make things more challenging.