The Effect of Interval and Continued Trainings with Citrus Aurantium on Pain Threshold and Motor Balance in Elderly Rats

Background and objectives: Aging is a natural phenomenon associated with a decrease in physical fitness factors and increases in chronic pain. The present study aimed to investigate the effect of High Interval Intensity Training (HIIT) and Moderate Intensity Continued Training (MICT) with Citrus Aurantium (CA) consumption on pain threshold and motor balance in elderly rats. Material and Methods: Forty-nine elderly rats were randomly divided into 1) control, 2) MICT, 3) HIIT, 4) MICT+CA, 5) HIIT+CA, 6) CA and 7) sham groups. Groups 3 and 5 performed HIIT at a speed of 25-25 m/min, and groups 2 and 4 performed MICT at a speed of 25-20 m/min; also, groups 4-6 received 300 mg/kg/day CA peritoneally. The pain and motor balance tests were evaluated using a hot plate and rotarod devices respectively. The Kolmogorov-Smirnov test was used to investigate the normal distribution of findings and one-way ANOVA with Tukey’s post- hoc tests was used to analyze of findings (P≤0.05). Results: CA, MICT, HIIT, MICT+CA, and HIIT+CA significantly increased pain threshold and motor balance (P<0.05); MICT+CA (P<0.05) and HIIT+CA (P<0.05) significantly increased pain threshold compared to CA, MICT, and HIIT, and HIIT+CA significantly increased pain threshold compared to MICT+CA (P<0.05). Conclusion: Although CA, MICT, and HIIT alone can enhance pain threshold and motor balance nevertheless it appears that MICT+CA and HIIT+CA have a better effect on the increase of pain threshold, so the effects of HIIT+CA can be higher than MICT+CA.