"Biggest Loser Couples" contestants are looking noticeably slimmer this week. There's always a point mid-season where their fat-burning, muscle-building hard work pays off at a visual level. Double chins are receding, stomachs are less flabby, biceps emerging. Just imagine how much stronger hearts, lungs and circulatory systems have become as they push morbid obesity away. Here's a quick recap on a muddy and sandy week around the ranch.

Two Teams Score Exclusive Gym Rights -- In a surprise Pop Challenge, teams ran up and down a steep hill grabbing from a set of 100 keys to try and open the gym. Only two keys fit the lock. Brown and Pink teams were the lucky winners, rewarded with sole access to the gym this week. Everyone else, including Bob and gym-loving Jillian, were freaking out as workouts headed into the great outdoors.

If You Don't Have a Gym, Improvise -- Biggest Losers still shed incredible weight this week without access to a gym. After a handful of contestants ate mud during a spontaneous mud-wrestling fight, Bob's team sucked sand at the beach like a bunch of NAVY Seal recruits by jogging in foot-swallowing sand, lifting benches, driftwood and garbage cans, and commando crawling. Outdoor-phobe Jillian had her team inside lifting firewood logs, then outside pressing up and out of the pool rep after painful rep. You don't need gear to get a great workout, just imagination.

TRX the Fat Away -- Bob set-up a TRX Suspension Trainer system around a tree limb and suddenly Biggest Losers were lunging, pressing and pulling their bodies at new angles, no gym required. Check out the Biggest Losers TRX-ing away, along with gallery full of TRX offerings. I'm wishing I had a set of TRX straps strung through a TRX anchor to spice up my at-home fitness regimen.

Empty Gym versus Busy Gym -- Do you prefer quieter hours at the gym or a packed house? Brown and Pink may have the gym to themselves this week, but they can't feed off the life and energy of the larger group. The sweatier the better for me.

Row For Immunity -- Black team's Dane beat Green's Laura and Tara in a rowing contest for immunity. Good thing Dane won because he lost only four pounds, which would've landed him on a plane ride home.

Sometimes Your Body Hangs On to Weight -- At least that's what it seems like from watching dozens of Biggest Loser weigh-ins over the last few seasons. Kristin gained two pounds last week, then dropped 12 this week. If you're doing everything right on the diet and fitness front, but that scale won't budge, stay the course. Put the gallon of ice cream away.

• Beginning runners should beware of running too fast, says Bob. This common mistake leads to side stitches and shortness of breath. To prevent, try focusing on deep breathing and take walking breaks.
  
• Start off your day with whole grain carbohydrates. Jillian reports their fiber aids in digestive health, and recent research shows whole grains may reduce the risk of heart disease, cancer and diabetes. My kids think 100 percent whole wheat bread is white bread -- we're on the right track.