\- less structured than interval; varying work times (similar to a game such as soccer)
\- easy running (70% VO2max) combined with hills or short, fast bursts (85-90% VO2max); same as HRR (jog, sprint, jog, sprint, jog, etc) 20-69 min total
\- can be adapted for cycling and swimming
\- benefits are likely to include enhanced VO2max, increased lactate threshold, improved running economy and fuel utilization