This study aimed to analyse the changes in the biomechanical and psychophysiological responses, and the body mass of trailers in a small-distance (44 km and 1520 m elevation gain) trail competition performed in tropical conditions. Methods: Ten trained trailers (8 men, 2 females; age: 42.0 ± 5 years, body mass: 65.57 ± 5.4 kg, height: 174.9 ± 5.9 cm BMI: 21.71 ± 2.1, Maximal Aerobic Speed (MAS): 16.6 ± 2.1 km·h-1) volunteered to take part in the competition, comprising eight laps of 5.5 km. At the end of each lap, the trailers had to stop for 10 min to perform tests measuring 1) the maximal horizontal force (F0), theoretical maximal running velocity (V0) and maximal power output (PO) during a 30-m sprint; 2) the vertical oscillations and maximal relative force during a 30-s treadmill submaximal run; 3) the perceived exertion and pleasure; and 4) body mass. The pacing, stride variations and heart rate were continuously recorded during the race. Results: The variations of PO (W·kg-1) during the 30-m sprint and perceived pleasure were significant (p = 0.003 and p = 0.02, respectively) influencing factors of pacing. A significant decrease (p the first and last laps. Fraction of MAS and MAS were significantly (p = 0.004 and p = 0.04, respectively) related to the trail performance. Conclusions: Training programmes could be proposed that include the increase of MAS, fraction of MAS and lower limb PO. During the competition, it could be interesting to plan a drinking programme to avoid potential thermoregulatory impairment, as well as psychological strategies to increase pleasure.