New Hack for Bigger Lifts?

Study Shows Palm and Sole Cooling Could Improve Performance

In the ever-evolving world of strength training and athletic performance, athletes and researchers are constantly seeking innovative ways to enhance peak performance. One emerging area of interest is the application of cold to the extremities, specifically the palms of the hands and the soles of the feet, during resistance training sessions. This noninvasive cooling method, known as interset distal cooling, has shown potential to improve workout outcomes by increasing muscle activation, reducing fatigue, and enhancing overall training volume.

How does distal cooling work?

The application of cold substances to the palms and soles is theorized to augment resistance training performance through several mechanisms. The main areas of performance benefits obtained by cooling these extremities is through enhanced stimulation of the central nervous system (CNS), leading to increased excitation and motor unit recruitment in the working muscles. This enhanced stimulation can result in greater force production and the ability to perform more repetitions before reaching fatigue. Other considerations relate to decreasing the temperature of blood, thus impacting temperature sensitive enzymes associated with muscle contraction, or limiting the amount of blood lactate accumulation. But studies indicating no change in lactate accumulation with distal cooling have also been shown. leading to some confusion as the efficacy of this modality.

Additionally, distal cooling is believed to reduce the sensation of distress during exercise (as measured through RPE), allowing individuals to tolerate more exertion and achieve higher training volumes. This reduction in perceived exertion could be attributed to the peripheral stimuli affecting the CNS, making the workout feel less taxing than it actually is.

What does the research say?

Several studies have explored the effects of palm and sole cooling on resistance training outcomes. For instance, research by Kwon et al. demonstrated that palm cooling during bench press exercises led to a statistically significant increase in training volume and muscle activation compared to a thermoneutral condition (no added cooling or heating). Participants also reported lower rates of perceived exertion, suggesting that cooling made the exercise feel less strenuous.

The article referenced for this blog states, “Several studies reported that cooling the palms or soles at 10 or 15 degrees C between sets of RT (resistance training) statistically increased total training volume and muscle activation, and one study reported that interset palm cooling elicited longterm gains in maximal strength comparable with using performance enhancing drugs.”* Another study by Cai et al. found that foot cooling between sets of leg press exercises resulted in more repetitions and greater muscle activation compared to passive recovery. These findings suggest that cooling the soles can be an effective strategy to enhance lower-body workouts.

The problem is not all research has shown these results. For example, a study on back squats found no significant differences in muscle activation or work capacity between cooling and non-cooling conditions, despite a reduction in perceived effort. On the contrary, increases in exercise induced core body temperate have been linked to fatigue and distal cooling rapidly decreases core body temperature, allowing aerobic endurance-based athletes the benefit of reduced fatigue. The same type of increased core body temperature is not found in short bouts of high intensity resistance training, making it unclear how distal cooling may impact performance in an environment lacking a rise in internal temperature. Contradictions in study findings indicate a need for further research into this topic.

Why isn’t everyone doing this?

While the potential benefits of interset distal cooling are promising, several challenges exist in the current body of research. As with many other high performance protocols, limited access to the the optimal tools and equipment can vary outcomes. Variations in cooling duration, temperature maintenance, and the methods used to assess muscle activation can influence study outcomes. Small sample sizes and lack of longitudinal studies make it difficult to draw definitive conclusions about the long-term effects of this method.

To address these challenges, future research should aim to standardize cooling protocols, include larger and more diverse participant groups, and control cooling methods and time prescriptions. Care should also be taken to reduce the possibility of placebo effect. Reliability measures for EMG data should also be a focus, with specific EMG procedures ensuring accurate analysis of muscle activation during sets.

Could this method work for you?

Given the noninvasive nature of interset distal cooling, this potential performance enhancing method can be explored safely for effectiveness on an individual level. Although there is not enough research to definitively prove its efficacy, athletes and coaches can explore the potential performance enhancing benefits that this legal and relatively accessible protocol provide. Although none have been indicated, practitioners should take care to control for any potential injury risks associated with this method. For more details on how to give this method a try refer to the article referenced here.

Have you ever tried interset distal cooling? Has it worked for you? We would love to hear your experiences with this method!

Reference:

*Burke, Ryan & Mcmahon, Gerard & Schoenfeld, Brad. (2024). Cooling Down to Level Up: Does Interset Palm or Sole Cooling Enhance Resistance Training Performance?. Strength & Conditioning Journal. 46. 10.1519/SSC.0000000000000855.