By Lori Incledon, LPTA, LATC, CSCS, NSCA-CPT, RPT

You’ve just repped out the last set during a tough weight training session and are feeling invincible. Then dreadful thoughts of “cardio” enter your head. “I have to endure another 45 minutes my already limited time on a piece of cardio equipment because ‘I have to get the cardio in.’” Of course you need to do your cardio – you’ll get big and bulky if you train exclusively with free weights, right? You’ll never lose any fat by weight training alone. And weight training can get boring too. Every day, the same routines. If these comments echo your thoughts, then you’ll be amazed with the latest craze to hit the fitness scene. It’s called interval training and although it may sound like an innovation, it really is a new twist to an old program called circuit training. If you want to burn fat, increase and tone muscle, improve your cardiovascular system, increase your muscular strength and endurance, and do it all in the shortest time possible, then interval weight training is for you.

What is Interval Training?
For those who have read the last issue and already turned their cardiovascular workouts into interval workouts, this will be a review. Interval training involves sets of repetitions (intervals) that are performed at variable exercise-to-rest ratios [1] or work-to-recovery ratios (WRR). An exercise interval is a continuous multiple sequence or whole body activity of supramaximal intensity. Because intervals are so intense, they can only be performed for a short period of time. Certainly one benefit of interval training is that you will practically cut your exercise time in half - but it will seem like you doing even more work because of the speed and intensity of the workout.

Why Should I Go Interval?
You want sleek muscles, no fat, a strong heart, and a training program that takes less than 1 hour, three times a week. Are you dreaming, girl? If so, then interval training is a dream come true. As Vern Gambetta, President of Gambetta Sports Training says, “You definitely get the biggest bang for your buck when you weight train in circuits or intervals. You gain strength, get lean, and improve your cardiovascular fitness all at one time.” Several studies can back up Gambetta’s statements. One study of men and women exercising on a weight machine circuit of 10 stations for 3 circuits per day (approximately 22.5 minutes/day) for 3 days/week, showed significant increases in lean body weight, flexed biceps girth, treadmill endurance time, VO2max in the women only, flexibility, and strength. Significant decreases were found in selected skinfold measurements without a change in body weight which suggests fat loss. The researchers also concluded that circuit weight training is a good general conditioning activity because it involves more than one component of fitness [2]. Still not convinced to give up your cardio? Well one group of researchers found that a circuit weight-training program was better in improving strength and changing body composition than a running program [3]. This same group then proved that a circuit weight-training program is just as beneficial as a circuit weight-training/running program (where a 30 second sprint is performed in between each exercise) in terms cardiovascular endurance, strength, and decrease in body fat percentage [4].

How Do I Go Interval?
Interval weight training is a marriage between strength and endurance training. By combining these modes of exercise, you can stimulate your body to new gains both physically and psychologically. Interval training might be the way to climb over a plateau and spice up your workouts. You can base your weight-training intervals on either repetitions or time. Let’s design an interval weight program consisting of a circuit of different exercises performed in a WRR of 1:1. For work based on repetitions, time how long it takes to perform15 repetitions of an exercise and then rest for that same amount of time. For work based on time, work for a specific amount of time, like 30 seconds, and rest for 30 seconds. Get in as many reps as you can during that time. Your intensity during the weight or work session should range from 40%-70% of your 1 repetition maximum – how much weight you can lift one time. As your conditioning improves, maintain your intensity and decrease your rest ratios or increase your intensity and maintain your rest ratios for variety. Gambetta says that the wild card in interval training is intensity – or how hard you are willing to go. It is always a good idea to consult a physician before beginning any new exercise program, especially one as intense as interval training. You should have a basic fitness level before embarking on an interval program since it is advanced and physiologically demanding. Interval weight training more than three days a week for more than 30 minutes will likely lead to overtraining and injury. Stick with a five-minute warm-up, 5-minute cool-down, and 20 minutes of interval weight training.

Sidebar – The Matrix
Vern Gambetta, MS, (www.gambetta.com) and Gary Gray, PT developed this excruciating circuit. It works every muscle, and then some. This is an advanced circuit and shouldn’t be attempted if you’re a beginner. If you can master the Matrix, then you are an interval queen!
The Matrix was designed to provide total body training in all three planes. It is composed of a pressing sequence (3 exercises), a curling sequence (3 exercises), a lunging sequence (3 exercises), and lunge-to-press sequence (3 exercises). Each exercise is performed 6 times (3 per side). The total circuit is 72 reps and you should aim for a target of 1:45-2:00 minutes for one total circuit.

Progression
Perform each complete sequence (6 reps of each exercise).
Perform total circuit with body weight, then with dumbbells, then a bar.
Perform with weights (not for time), regain complete recovery between sets, x 2 sets.
Perform with weights (not for time), regain complete recovery between sets, x 3 sets.
Perform with weights (for time), regain complete recovery between sets, x 3 sets.
Perform with weights (for time), 1:2 work rest ratio, x 3 sets.
Perform with weights (for time), 1:1 work rest ratio, x 3 sets.
When you can perform 3 sets with 1:1 in 1:45 –1:55 – add weight (5-10%)!

THE MATRIX Sequences
Pressing sequence (18 reps)
Sagittal Overhead Press x 6
Frontal (“Y”) Overhead Press x 6
Cross Overhead Press x 6

Curling sequence (18 reps)
Alternating curls x 6
Alternating Upright Rows x 6
Cross Uppercuts x 6

Reaching Lunging sequence (18 reps)
Front lunges (sagittal) x 6
Lateral lunges (frontal) x 6
Rotational lunges (transverse) x 6

Reaching Lunging to Press sequence (18 reps)
Front lunges to press (sagittal) x 6
Lateral lunges to press (frontal) x 6
Rotational lunges to press (transverse) x 6

Sidebar – Sample Free-Weight or Machine Circuit
A free-weight circuit is easier to perform in a crowded gym, but some gyms already have a weight machine circuit set up. This is the perfect situation, because it is difficult in most gyms to get on a piece of equipment exactly when you want it. Perform 15 reps for each exercise or however many reps you can get in 15-20 seconds. Rest for the same amount of time that it took you to exercise (1:1 WRR) and move on to the next exercise. If you “have to get your cardio in,” add a bike sprint or treadmill sprint in between weight exercises. Don’t time your “rest” ratio until you have reached an intense speed on the bike or treadmill. A sample weight machine or free weight workout:
Leg Press or Squat x 15
Bench Press Machine, Dumbbell or Barbell x 15
Lying Leg Curl or Deadlifts x 15
Row Machine, Dumbbell or Barbell x 15
Standing Calf Raise Machine, Dumbbell or Barbell x 15
Seated Overhead Press Machine, Dumbbell or Barbell x 15
Preacher Curl Machine, Dumbbell or Barbell x 15
Tricep Extension or Kickback x 15
Abdominal Crunch Machine or Dumbbell Crunches x 15
Back Extension Machine or Hyperextensions x 15

Sidebar – Methods to Measure Intensity – Heart Rate Maximum
This method is a little difficult and sometimes inaccurate because heart rate doesn’t always correlate with effort, but if you wear a heart rate monitor it will simplify things. For safety for beginners, using the age-predicted maximum heart rate formulas and a heart rate monitor to assess your intensity is essential. To determine a percentage of your heart rate to work at for your intense work sessions, calculate your age-predicted maximum heart rate (APMHR) and multiply it by the appropriate percentage. The American College of Sports Medicine recommends staying between 60%-90% of APMHR for work sessions. For a beginner, work ratios should be between 60%-80% of APMHR and then can progress up to 85%-90%. Example for a 30 year-old woman beginner who wants a 70% work bout:
APMHR = 220 – age (220-30) = 190 x .70 = 133’
You can also arrange the heart rate percentage to reflect your selected recovery heart rate. Let’s say that our beginner wanted to recover at 60% of her APMHR.
APMHR = 220 – age (220 –30) = 190 x .60 = 114
Then she wouldn’t begin her next interval work repetition until her heart rate had recovered to 114 beats per minute.

Sidebar – Methods to Measure Intensity – Ratings of Perceived Exertion (RPE)
This method allows you to measure intensity and effort by the way it feels to you and then giving it a number. Some use a 15-point Borg scale with a 6 being no exertion and a 20 being maximal exertion. A Category-Ratio scale can be used with 0 being nothing at all and 12 being absolute maximum. But let’s simplify things and rate effort on a 0-10 scale, where 0 is no effort and 10 is maximal effort. We can then correlate these to percentages and say that a 5 is 50% effort and that a 10 is 100% effort - you can’t do any more than that. A 5 is where you should be at the end of your warm-up, a 3 at the end of your cool-down, and 9-10 for advanced interval trainers during a work session.

References
1. Plisk, S.S., Anaerobic Metabolic Conditioning: A Brief Review of Theory, Strategy and Practical Application. Journal of Applied Sport Science Research, 1991. 5(1): p. 22-34.
2. Wilmore, J.H., et al., Physiological alterations consequent to circuit weight training. Med Sci Sports, 1978. 10(2): p. 79-84.
3. Gettman, L.R., et al., The effect of circuit weight training on strength, cardiorespiratory function, and body composition of adult men. Med Sci Sports, 1978. 10(3): p. 171-176.
4. Gettman, L.R., P. Ward, and R.D. Hagan, A comparison of combined running and weight training with circuit weight training. Med Sci Sports Exerc, 1982. 14(3): p. 229-234.