Complex sentence: He also loves triathlons (Olympic distance) during the summer months and last year he again successfully completed the Half Ironman UK event in Dorset, and this year he has signed-up for several more similar events.
Split into simpler sentences: He also loves triathlons (Olympic distance) during the summer months and last year he again successfully completed the Half Ironman UK event in Dorset. This year he has signed-up for several more similar events.