It's that time of year when the motivation to train begins to fade, and the real battle to keep exercising is joined. Unfortunately the the physiological facts are not on your side.
Aerobic capacity starts to diminish within about a week of inactivity, and the loss becomes significant after about three weeks.
Similarly, muscle strength starts to decline after about a week. Connective tissue begins to thin and weaken, and even bones become a bit less dense over time.
"Unfortunately, what I've found, and everyone has a different answer, but it's about twice the amount of time to build back," said Cristin Van Driel, a certified personal trainer with Form & Fitness in Grafton and Mequon.
On the plus side, sustaining even 20% of a previous training load will preserve much of an athlete's fitness base.
So how do you get back into the swing of a healthy excecise routine?
Tom Held of JSOnline.com has some helpful tips:
"Take what you can get: Circumstances may make those four-hour weekend training sessions impossible.
But don't sacrifice a good, 30-minute run because it's not the 10 miles that would be ideal.
Knaack, mother of a son, 5, and a daughter, 6, has become expert in incorporating her workouts in their play activities: a trip to the pool provides them with playtime and allows her to turn a few laps; and the ice rink is another play area where she can burn calories and maintain an aerobic base.
It's also important to maximize the reduced training time with consistency, and avoid the weekend warrior syndrome.
"There's a window of a training effect," Labisch said. "You have to do something within every four days or you lose the effects."
Be patient: Labisch lays out a 12-week program for athletes starting out again from square one.
Blocked out in three-week increments, it starts with three workouts per week and adds days and volume in each subsequent block. That allows soft tissue, muscles, bones, aerobic capacity and the psyche to undergo the necessary transformation to withstand competitive-level training.
Toe the line: Few things motivate like putting a race on the calendar.
"If I have something that I'm training for, then I do (train)," said Gonya, who has overcome back injuries in her marathon, triathlon, cycling and football career. "If it's not an event, make it a physical goal. Put a date on it: 'I want to be able to run a 10K at this pace and I want to do it by a specific date.'
"It keeps people away from that aimless drift."