Mike Boyle is one of the best in the business - and by some is regarded as THE very best. He has trained professionals, collegiate athletes and Olympians. The guy is very legit.
Please follow this link to check out 8 ideas for things to incorporate into your warm-ups, and/or do on your own.
And this next link gives you info on 3 additional exercises you can (and should do) as part of warm ups to improve hip flexibility - something almost everybody can use help with! *it is titled how to fix back pain, but the key is the hip mobility… "fixing" back pain would just be a bonus.