Football always made sense to Pat Angerer. He liked the structure of playing the sport at its highest level, whether it was in college at Iowa or in the NFL with the Colts. Being micromanaged – being told when to work out, when to eat, who to tackle, etc. – worked for him.

But when Angerer's playing career ended, he missed the discipline that comes with following orders. Former Army service member John Davis, a friend of Angerer's since second grade, felt the same way after leaving the military.

So Angerer and Davis, using their shared experience, teamed up to author a book – "#FreedomChallenge: 90 Days To Your Personal Best" – designed to provide the structure they both craved, and written to help folks grow physically, mentally and emotionally.

"(After your playing career) you get undisciplined, and then you create bad habits, and then you stop doing the things that made you great," Angerer said. "And then you get out of a culture and kind of alienate yourself a little bit. This book gets people part of a culture, gets people disciplined, gives them goals, gives them a purpose."

Angerer, a linebacker, was a second-round pick of the Colts in the 2010 NFL Draft and appeared in 54 games (39 starts), totaling 328 tackles over his four-year career. Davis spent 10 years in the military, including as an Infantry Squad Leader in the 101st Airborne Division, and was deployed twice in Afghanistan. The blending of the military and athletic experience was a foundation for putting the #FreedomChallenge together.

"We want to give people and opportunity to push themselves, because nobody else is going to do it for you," Davis said, "and also to connect the military mindset with the athletic competitive spirit, and give that to people form our combined experience." 

But Angerer and Davis compiled the book in a way that everyone – not just ex-athletes or service members – can benefit.

"I made sure I was comfortable a lot," Angerer said of his post-playing career. "You do the things that are easy — you don't necessarily go out of your way to live an easy life, but once you have success, you start doing some things that make life a lot easier. And you forget that the reason why you're able to have that success is through discomfort, and discomfort breeds growth. Even though these are little discomforts, there can be some growth there. You get a feeling and a sense of appreciation of when it's good — if it's always sunny, do you even appreciate it? I think in order to see the light, there's got to be darkness. And I think that's what we'e trying to get out of that."

FreedomChallenge is an easily-digestible 62 pages. The 90 days of challenges are broken up into three 30-day phases, with weekly challenges, discomforts and workouts. Angerer and Davis had current and former athletes, as well as active duty military members and veterans contribute workouts to the book.

An example of a challenge: Set a sleep schedule and stick to it.

An example of a discomfort: Repair a relationship with a family, friend or co-worker and have an uncomfortable conversation.

("It's easy to think we should avoid discomfort to seek to live the most comfortable life as possible," Davis said. "But that's not really how people are going to be happy.")

An example of a suggested workout (submitted by WWE Champion Ettore Ewen, a teammate of Angerer's at Iowa):

• Barbell split squat 4x5
• Barbell jumps 4x10
• Front squats 2x5, 1x4, 2x3
• Cable pull throughs 3/15
• Walking barbell lunge 3x12
• Seated V-twist 2x15
• Barbell complex 2x6
• Barbell side bends 2x10

Throughout the book, there are reminders, discomforts, challenges and recommended reading/viewing materials designed to address mental health, too.

"That's something we truly realized — yeah, the physical workouts are great, staying active is awesome," Angerer said, "but the mental aspect of it plays a bigger role."

You can buy Angerer and Davis' "#FreedomChallenge: 90 Days To Your Personal Best" on Amazon, and a portion of the proceeds from each book will be donated to the Suicide And Remembrance Flag, a foundation which aims to break the stigma of mental health, suicide and seeking treatment in order to help prevent suicide in veterans. Davis said he's lost more of his military friends to suicide than in combat.

So whether it's through providing a communal purpose with the content of the book to veterans, or in donating part of the proceeds to work toward improving veteran mental health, there are several specific benefits Angerer and Davis' book can have on the military community in the United States.

"We still have a country where 7,000 veterans take their lives every year," Davis said. "It's something that I think society has kind of allowed to fake into the background because it's been normalized — anything that happens enough becomes normalized, right? So we wanted to put our money where our mouth is and do something good with some of the proceeds from the book." 

For Angerer, writing the book and talking through it with Davis was therapy in itself. It already helped him become a better version of himself, and Angerer expects the book to help those who read it experience the same accomplishment.

"I just hope it helps people," Angerer said. "If it helps one person, then it's a win."