In order to keep your body strong and balanced year round, it is important to rotate phases throughout your training year. As you near big races, the mileage increases and while you are beginning a new phase, you should focus on other physical attributes - strength and power being one of them. When you increase your strength, your body can handle more miles and faster miles going into the next race.
Jill here, in preparation for her 2nd half and first full Ironman focused on deadlifts and chin ups. She got very strong and is just trying to maintain her strength, mobility and power gains as her training intensifies. Here, Jill is showing some of the benefits with a body weight chin up.