Thermography for defining efficiency of cryotherapy modalities in sport: Comment on: Alexander, J., Selfe, J., Birdsall, D., Rhodes, D. The effects of three different cryotherapy modalities on skin surface temperature across squad positions in a population of male, rugby union players. Int J Sports Physical Therapy. 2020;15(2): 210-220.

Abstract

Infrared Thermal Imaging (TI) is well evidenced for the quantification of skin surface temperature (Tsk) and abundantly used within cryotherapeutic research [1–4]. We have published several articles recently on the effects of local cryotherapy with the physiological effects quantified through Tsk via TI techniques [3,4]. The remit of those studies was based on two key themes: (i) Tsk response to contemporary cooling modalities compared to traditional applications (ii) Tsk and physiological response to contemporary cryo-compressive devices with varying pressure adjuncts for the management of musculoskeletal injury or as a recovery strategy in sport. Comparison of traditional methods of cryotherapy modalities to modern alternatives in sport provided justification to progress the knowledge in theme (i). Literature to support theme (ii) was evidently lacking and developed naturally to combine multiple contemporary cooling modalities that operate cooling and compression simultaneously. All of which quantified Tsk through infrared TI and followed guidance by Moreira et al. [2], for the setup of thermology capture. Several investigations utilize infrared TI as an objective measure to quantify the efficiency of common cooling modalities used in sport by way of Tsk. Preferences on the choice of cooling modality often amount to whether optimal temperatures can be achieved in the target tissues and are quantified via Tsk. In our recently published manuscript in the International Journal of Sports Physical Therapy [3], we aimed to determine differences in the cooling ability of three different cryotherapy modalities (Wetted Ice, Crushed Ice and CryoCuff®), in a specific sports population through physiological measures of Tsk using TI. Physical characteristics vary between playing positions in rugby union due to the demands of the game, and in consideration of this, levels of adipose tissue vary and influence interference on the efficacy of local cooling applications. To date, although studies consider a comparison of multiple cooling modalities, typically methods fail to report heterogeneities of participants or properties of the modality. A therapeutic temperature range for target Tsk following local cooling applications of 10–15°C has previously been proposed [1]. This typically represents a Tsk range whereby physiological responses occur and are often referred to in publications related to cooling parameters achieved by cryotherapeutic modalities [1]. Results from our study [3] demonstrated differences in Tsk response to cooling with wetted ice displaying the greatest reductions. The main findings however highlighted not only the significant differences between Tsk when comparing between the three different modalities (Wetted Ice; Crushed Ice and CryoCuff®) but also across playing positions (forward and backs). Results suggest using TI, to determine the effects of such variable (physical characteristics) is useful to consider in relation to the efficacy of cryotherapeutic applications in the assumption that adipose tissue levels vary between these positional characteristics. This may appear obvious, and cooling applications in terms of duration should be altered to account for the insulating effects of adipose tissue. That said, no evidence was available that compared contemporary cooling to traditional methods, nor contemplated the physical characteristic differences in playing position in specific sports populations at the time. Evidently, analysis using infrared TI results indicates that potential phase change differences alongside characteristic variables may both be responsible for variance in target Tsk responses [3]. In terms of an applied practical impact, individualization of local cooling applications and choice of modality is imperative for optimal response. From TEMPERATURE 2021, VOL. 8, NO. 2, 105–107 https://doi.org/10.1080/23328940.2020.1819517