Karen Mackin

Karen Mackin

  • Peaks Coaching Group Coach Karen Mackin
  • Peaks Coaching Group Coach Karen Mackin
  • Peaks Coaching Group Coach Karen Mackin
Acton, Massachusetts

USAC Level 1 Power Certified Coach
USAT Level 1 Coach, Junior Certified
USATF Level 1 Coach
AFAA Certified Personal Trainer
PCG Elite/Master Coach
Coaching Focus: Tri, Running, Road, CX, Time Trial, Juniors, MTB


My athletic career began over 30 years ago when I signed up for Track and Cross Country in High School. From 5ks to marathons, I spent a lot of time just enjoying being outside and feeling fit. It wasn't until I was introduced to bike racing in the late 1980s that the competition grabbed me. I found that with a little hard work, I could get results! Since then I have become addicted to the pursuit of knowledge about training and racing. At first I applied that knowledge to my own training, and pretty soon I was coaching/mentoring my bike racing teammates. When I switched my athletic focus to triathlon, I left my engineering/software systems job to focus on both raising my family and building a business as an endurance coach. In 2005 I bought my first power meter, sent my coaching resume to Hunter Allen, and have been coaching with Peaks Coaching Group ever since.

Coaching philosophy

My philosophy is based on my experiences in life, racing, and coaching. I believe in a holistic approach, where sport is balanced with family, work, and relaxation. It’s very important to know what your priorities are and structure your training/racing around those priorities. Every athlete is unique and deserves a training program that starts at his/her current ability and evolves as fitness improves. I believe the best way to do this is through building a strong athlete-coach relationship based on mutual trust and good communication. I work best with athletes who are willing to meticulously log and/or download their workouts. I love it when I know exactly what my athletes do (or don’t do) for every workout; this enables me to really dial into what they need in order to succeed at whatever goals they have set for themselves. The more you put into communication and relationship, the more you get out!

Notable achievements
  • Triathlon: Ironman USA Lake Placid, USAT All-American, Competed at USAT Age Group Nationals, ITU World Championship in Olympic Distance, and Ironman 70.3 World Championship
  • Cycling: Former Nationally-ranked Category 2 Cyclist, Raced extensively at the National Race Calendar Races. 
  • Speed Skating (Ice): Competed for 8 years in both long and short track events, Won numerous races and awards, including 2nd place in National Marathon Speed Skating Championships
Athlete testimonials

I can't thank you enough for helping me get to the IMLP finish line smiling! You respected my life, my health, and my emotions. Whenever I saw my glass as half empty due to health and life challenges, you helped me see it as half full by focusing on my incremental achievements. Your ability to continually adapt my plan as new challenges arose not only got me to the finish line, but also helped me take FIFTY minutes off last year's marathon time! - Nicole Sheahan 

Karen takes our weekly call very seriously and has, on a number of occasions, called while traveling and on vacation. This is massively appreciated. Karen has been great to work with -- I enjoy the weekly call and review of workouts, and also appreciate the manner in which she keeps all my goals in mind (athletic and non) in formulating my ATP. She is very knowledgeable indeed. - Greg, South Africa

Karen is an awesome coach and I am so glad to have her. She pushes me to achieve more than what I think I'm capable of and yet balances it with my heavy work/family schedule. Her weekly Skype sessions are a gem! - Lynette, Singapore

Karen is the perfect coach for me. She provides well-thought-out annual, monthly, weekly, daily plans, with the ability to make adjustments if needed. If I'm doing things well, she tells me; if I'm not, she is kindly but brutally honest. She also takes the time and interest to "get inside my head" to see what makes me tick. She drives me to the edge, but never over the edge. She brings out the very best she can and has an uncanny ability to keep me motivated to do better. I never want to disappoint myself or Karen. Karen has a very real personal interest in my success while maintaining the professional distance all great coaches have. - David, Massachusetts

I have to say that Karen’s guidance and training have directly contributed to my success this year (Masters CT State Criterium Championship, third in the Masters CT State Road Race Championship, a number of top finishes in Criteriums, first in the 10K CT Senior Games with the 2nd fastest time of all age participants). I am 65 years old. - Jeff

I've been using Karen Mackin as my tri coach for a year and a half, and under her guidance I have gained confidence and improved my times in all three sports. Karen has helped me prepare for numerous sprint and Olympic distance triathlons, as well as for time trials and multi-day cycling events. Her detailed training plans, frequent analysis of my power files, emails and phone calls, and nutritional advice were extremely helpful as I trained to complete Ride the Rockies 2008. With her coaching expertise I was able to successfully complete my first multi-day cycling event. Karen’s experience as a triathlete and her energetic coaching style are both motivational and encouraging. She makes you want to work hard to achieve your goals. I continue to learn new ways to train and new skills and strategies that will help me achieve my goals, whether in cycling, running, swimming, or strength. Thanks, Karen!  - Becky
View Karen's athletes' accomplishments >

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