The Effects of Post-Exercise Cold Water Immersion on Neuromuscular Control of Knee

Abstract

To date, most studies examined the effects of cold water immersion (CWI) on neuromuscular control following exercise solely on measuring proprioception, no study explores changes in the brain and muscles. The aim of this study was to investigate the effects of CWI following exercise on knee neuromuscular control capacity, and physiological and perceptual responses. In a crossover control design, fifteen participants performed an exhaustion exercise. Subsequently, they underwent a 10 min recovery intervention, either in the form of passively seated rest (CON) or CWI at 15 °C. The knee proprioception, oxygenated cerebral hemoglobin concentrations (Δ[HbO]), and muscle activation during the proprioception test, physiological and perceptual responses were measured. CWI did not have a significant effect on proprioception at the post-intervention but attenuated the reductions in Δ[HbO] in the primary sensory cortex and posterior parietal cortex (p < 0.05). The root mean square of vastus medialis was higher in the CWI compared to the CON. CWI effectively reduced core temperature and mean skin temperature and improved the rating of perceived exertion and thermal sensation. These results indicated that 10 min of CWI at 15 °C post-exercise had no negative effect on the neuromuscular control of the knee joint but could improve subjective perception and decrease body temperature.

Keywords: brain activation; cold-water immersion; knee; muscle activation; neuromuscular control.

Figure 1

The spatial profile of functional near-infrared spectral imaging (fNIRS) probes. The red circles indicate the 8 optical sources, the green circles indicate the 7 detectors and the black numbers (1–23) indicate fNIRS channels. The optical sources and detectors were positioned on the international 10–20 standard positions.

Figure 2

Changes in knee proprioception for control (CON) and cold-water immersion (CWI) conditions. AUC, the area under the receiver operating characteristic curve of the knee Active Movement Extent Discrimination Assessment test. PRE-EX, pre-exercise; POST-EX, post-exercise; POST-INT, post-intervention; 24 h POST EX, 24 h post-exercise. # significantly different compared with pre-exercise in CWI. $ significantly different compared with pre-exercise in CON. The values are shown as mean ± SD. p < 0.05 was considered statistically significant.

Figure 3

Changes in the primary motor cortex (ROI1, (A)), the primary sensory cortex (ROI2, (B)), and the posterior parietal cortex (ROI3, (C)) for control (CON) and cold-water immersion (CWI) conditions. PRE-EX, before exercise; POST-EX, after exercise; POST-INT, after intervention; 24 h POST EX, 24 h after exercise. * significantly different compared to CON. b significantly different compared to post-exercise in CON. $ significantly different compared to pre-exercise in CON. The values are shown as mean ± SD. p < 0.05 was considered statistically significant.

Figure 4

Change in core temperature (A) and mean skin temperature (B) for control (CON) and cold-water immersion (CWI) conditions. PRE-EX, before exercise; POST-EX, after exercise; POST-INT, after intervention; POST-Propri, the proprioception test after intervention; 0–10, during the intervention time. * significantly different compared to CON. # significantly different compared to pre-exercise in CWI. $ significantly different compared to pre-exercise in CON. The values are shown as mean ± SD. p < 0.05 was considered statistically significant.

Figure 5

Change in heart rate for control (CON) and cold-water immersion (CWI) conditions. PRE-EX, before exercise; POST-EX, after exercise; POST-INT, after intervention; POST-Propri, the proprioception test after intervention; 0–10, during the intervention time. * significantly different compared to CON. # significantly different compared to pre-exercise in CWI. $ significantly different compared to pre-exercise in CON. The values are shown as mean ± SD. p < 0.05 was considered statistically significant.

Figure 6

Change in rating of perceived exertion (A) and muscle soreness (B) for control (CON) and cold-water immersion (CWI) conditions. PRE-EX, before exercise; POST-EX, after exercise; POST-INT, after intervention; 24 h POST EX, 24 h after exercise; 0–10, during the intervention time. * significantly different compared to CON. # significantly different compared to pre-exercise in CWI. $ significantly different compared to pre-exercise in CON. The values are shown as mean ± SD. p < 0.05 was considered statistically significant.

Figure 7

Change in thermal sensation for control (CON) and cold-water immersion (CWI) conditions. PRE-EX, before exercise; POST-EX, after exercise; POST-INT, after intervention; 24 h POST EX, 24 h after exercise; 0–10, during the intervention time. * significantly different compared to CON. # significantly different compared to pre-exercise in CWI. $ significantly different compared to pre-exercise in CON. The values are shown as mean ± SD. p < 0.05 was considered statistically significant.