Despite the relevance of HIT for health and performance outcomes little is currently known regarding the effects of incorporating HIT in a concurrent training regime on acute molecular interference and subsequent chronic adaptation to long-term concurrent training.Indeed,studies independently examining the effect of endurance exercise intensity on concurrent interference are scare.One study suggested no role for endurance exercise intensity on interference in physically active females;however,training volume and frequency were comparably low and may have limited any potential interference effect seen with higher training volumes.Most existing molecular research has employed low-to-moderate intensity endurance exercise protocols(e.g.30-60 min at 65-70%,40-90 min at 55-70%),whilst none have directly examined the effect of endurance exercise intensity on acute molecular and chronic performance interference.As aforementioned,Coffey and colleagues observed that repeated sprints attenuated the anabolic response when performed concurrently with resistance exercise,and seemingly more so than in a previous study employing moderate-intensity continuous cycling.However,little is known regarding the role of more practical HIT models involving longer work intervals interspersed with periods of active or passive recovery on acute interference and subsequent chronic adaptation when performed concurrently with resistance training.