I may be a bit biased here because, in addition to being a running coach, I've also benefited from training with coaches throughout my years of running. But I do believe there are several advantages to getting personal attention and coaching advice. A running coach will use your running history, your current fitness level, and your goals to create a customized training program. With an individualized program, you'll run the mileage and intensity that's appropriate for your abilities and goals. A running coach can also give you technical analysis of your gait and running form, so you can make tweaks to improve your performance and avoid injury. He or she can also provide expert recommendations for running gear, nutrition, and hydration.
In addition to giving you personalized advice, a running coach is also a constant source of motivation and support. You can contact your coach whenever you have a question about your training. And regular training sessions with your coach will help keep you motivated to stay on track.
If you can't afford the expense of a personal coach, but you're looking for extra motivation and expert advice, you may want to search for a coach-led running group. Some specialty running stores offer free coach-led clinics or runs. Charity running groups also offer free coaching in exchange for fundraising. You may find coaching in a group setting even more beneficial than getting one-on-one coaching because you'll also get some running partners out of the deal.
Working with a running coach is not for everyone. Some runners prefer to train on their own and don't want to deal with the hassle of coordinating training sessions with a coach's availability. If you're extremely self-disciplined, have some basic knowledge about running and are willing to do research and learn more, you'd probably be really successful on your own.