Ammonia inhalants increase arousal but not necessarily performance [6]
What was studied? This study was designed to determine whether inhaling sharply from a flask containing ammonium carbonate improved measures of neuromuscular performance in healthy non-resistance-trained young men. Inhalation was done no more than 30 seconds before performance measurements after a warm-up for each of the metrics.
Why study it? Surveys of athletes, especially powerlifters, have found that many of them use ammonia inhalants to raise alertness and improve performance. However, the efficacy of this technique remains mixed, with one study finding that peak power improved in already-fatigued athletes, but other studies finding little effect. Some researchers have suggested that non-resistance trained athletes may benefit more from ammonia-induced arousal, but this hypothesis hasn’t been tested before.
What was(n’t) found? Ammonia inhalants reliably boosted heart rate, alertness, and the participants’ self-evaluation of how well they performed in the trials. However, there was no clear improvement in any of the three performance measures tested (hand grip and knee extension maximal voluntary contractions, or peak power during countermovement jumps).
How null was it? No power calculation was performed, so it’s not clear if these results could have been false negatives. The sample size was 14 participants, but the study was conducted as a cross-over trial. Based on quick calculations by the Examine editors, this study may have had the power to detect a medium to large effect.
Adding whey protein concentrate or hydrolysate to suboptimal carb intake didn’t impact 24-hour recovery in trained cyclists[7]
What was studied? The authors of this study investigated whether adding 0.3 g/kg body weight of either whey protein concentrate or hydrolysate to a post-exercise drink containing suboptimal amounts of carbohydrate (1.2 g/kg body weight — about half the needed dose) could help with next-day performance after a two-hour exercise bout in trained male cyclists. The initial exercise bout was designed to mostly, but not completely, deplete the athletes’ glycogen stores. Total energy intake was matched between conditions.
Why study it? Previous research has established that a sufficient amount of carbohydrates post-exercise can aid in endurance athletes’ recovery and boost future short-term performance after an intense exercise bout. However, a lot of athletes’ habitual carbohydrate intake doesn’t meet their carbohydrate requirements. Other research has suggested that adding some protein to post-exercise carbohydrates could help replenish glycogen stores more effectively by boosting glucose uptake via insulin-independent and -dependent routes. However, this research has mostly focused on short-term effects under eight hours. A more realistic test focused on next-day performance hasn’t been conducted. It’s also unclear whether intact protein or hydrolysates could be more effective for this purpose.
What was(n’t) found? Next-day 30 minute time-trial performance was not different between carbohydrate-only and either protein conditions, even though insulin responses were higher in both protein conditions. Ratings of perceived exertion weren’t different, either. Carbohydrate oxidation was lower on the second day than on the first under all conditions, suggesting that glycogen was not completely restored in any of the conditions.
How null was it? On one hand, this trial was designed to more closely mimic conditions more relevant to training athletes by measuring next-day performance using suboptimal carbohydrate amounts after undergoing rigorous, but not completely exhaustive, training. In that sense, it’s a bit more null than other experiments looking at shorter time frames. On the other hand, the study was powered to detect a large effect size and would have trouble distinguishing medium or small effects. Also, it does not rule out stronger cumulative effects over the longer haul, since it still only tested next-day performance. It also does not rule out benefits after completely exhaustive exercise. Indeed, one trial[8] that found benefits from adding protein to carbs using a more exhaustive time-to-exhaustion test, which bolsters this hypothesis.