Spring is here! For many, this is prime time to ramp up their exercise routine in order to get trim down in time for summer. And that’s why Pure TalkUSA is featuring the Nike Training Club app. Designed for women (but useful for all), it’s great for building cardiovascular endurance and was also one of the Huffington Post’s Best Fitness Apps of 2012. It offers over 90 comprehensive and custom-built workouts, and it’s totally free.