Physiological responses and agreement between two traditional lunging protocols for physical fitness training in untrained ponies

Lunging is a training technique commonly performed in a round pen or on a lunge line. This study investigated the effort intensity, autonomic responses, and method agreement in applying different lunging protocols to untrained ponies. Sixteen untrained ponies (aged 13.6 ± 6.3 years and weighing 358 ± 47.4 kg) were studied. Each pony underwent the same research-focused lunging program on a lunge line and, subsequently, in a round pen with a two-day interval between sessions. The heart rate variability (HRV) and effort intensity, indicated as a percentage of maximum heart rate (%HRmax), were determined pre-lunging, during lunging at distinct gaits, and at 30 min intervals for 120 min post-lunging. The correlation and method agreement between the two lunging methods were analysed. Ponies ran faster and covered longer distances during exercise on a lunge line than in a round pen. The effort intensity during cantering reached moderate levels (75.10 ± 2.39 % HRmax) with occasional high-intensity levels (88.07 ± 1.29 % HRmax) via both lunging methods. The HRV reached a minimum during cantering and returned to the baseline 120 min post-lunging. The HRV parameters (SDNN, RMSSD, LF, HF, SD1, and SD2) were strongly correlated (r_p ≥ 0.97 and p < 0.001 for all) with a large correlation effect size (R² > 0.85) and excellent agreement (average differences were within mean ± 1.96 SD) between the two lunging methods. In conclusion, lunging can elicit high physiological responses in untrained ponies, and both lunging methods demonstrate excellent agreement and yield similar physiological responses in these ponies.