Runners are always looking forward to the next grueling sprint or long weekend run, but the thought of lifting weights scares them off. Just like all athletes however, runners need to maintain a well-balanced workout regimen that focuses on each aspect of their body. Traditional workouts recommend lifting close to your max. A study published in the Journal of Strength and Conditioning Research is suggesting you alternate your weights instead. Known as velocity-based training, this allows you to tailor your workout each day to how you are feeling. A study showed that alternating weight provided a longer workout with less chance of injury and improved conditioning.
Source: https://www.runnersworld.com/news/a30899976/how-to-get-stronger