In the early days of group fitness when everyone wore leg warmers and exercised to Jane Fonda tapes, the warm-up portion of a typical cardio conditioning class included moves borrowed from ballet, jazz dance and yoga. Unending head turns, plié squats, bouncing side bends and inverted calf stretches in the downward dog position were all part and parcel of the typical “aerobic dance” warm-up.

As group fitness evolved in the 1980s, instructors became more educated about the true purpose of a warm-up. We started moving more and holding still less, employing a three-phase warm-up that focused on large body movements, small- or single-joint movement isolations (such as toe pointing and flexing) and static stretches.

In the 1990s, cardio group warm-ups progressed even further as research findings added to our body of knowledge. Although we retained a three-phase approach, the phases themselves changed. We replaced the small- or single-joint movement isolations with rehearsal moves, updated the large body movements and substituted single-joint dynamic stretches for the static stretches. These changes marked a paradigm shift in our approach to group fitness warm-ups.

The year 2000 has ushered in yet another dramatic and natural evolution in warm-ups. A growing body of research, anecdotal evidence and common sense are strengthening the case that the emphasis should be on movement. And like those leg warmers and Jane Fonda tapes, both static and single-joint dynamic stretches will soon be things of the past!

The new, improved “active range” warm-up narrows the previous three phases down to two. We have retained the rehearsal phase, but added a multijoint range-of-motion phase, which replaces the large body movements and single-joint dynamic stretches. What are the advantages of this new type of warm-up? What does it consist of in practical terms? And, most important, why and how can you update your own warm-ups to prepare your participants for another millennium of safe, effective exercise?

Warm-Up Goals and Benefits

Stated simply, the primary purpose of a warm-up is to prepare for action by gradually progressing the body from rest to vigorous activity. By doing this we avoid undue stress on the body, reduce the risk of injury to muscles and joints, and make the workout more comfortable. We achieve these goals through continuous, rhythmic movements. As muscles go into motion, they gradually produce more energy and release more heat than they do at rest. The aim should be to increase tissue, or core-body, temperature by about 2 degrees Fahrenheit from the start of the warm-up to the beginning of the cardio section of class. This temperature increase creates the following important exercise benefits:

Decreased Injury Potential. Most acute injuries involve muscle strains and tears (Garret 1983). These injuries primarily affect the muscle tendon junction where the center of the muscle converges with its tendon. Research has shown that these types of injuries are less likely to occur when the body is warmed through muscular activation (Safran et al. 1988). Warming the body increases the extensibility of the muscles and connective tissue. Compared to cold muscles, muscles warmed up through activity are more pliable. Also, the length of the muscle tendon junction increases under a given workload, helping prevent injuries during vigorous activity.

Enhanced Muscle Contractions. When warm, we move more efficiently. Our muscles contract more quickly and can exert more effort, enabling us to keep pace during the upcoming cardio workout.

Enhanced Oxygen Supply to Working Muscles. Repetitive movement raises blood temperature, permitting oxygen to be released more quickly from hemoglobin to help fuel the working muscles. Enhanced oxygen supply helps speed up the removal of carbon dioxide and other metabolic byproducts.

Increased Calorie Burning. The body metabolizes fatty acids and glucose at a faster rate when moving than when resting.

Increased Heart Rate, Blood Flow, Stroke Volume, Cardiac Output and Breathing Rate. The gradual increases help prepare the cardiovascular system for the vigorous workout to come.

Joint Protection. Range-of-motion activities trigger release of synovial fluid to help lubricate, protect and nourish the joints.

Quicker Nerve Transmissions. Nerve transmissions increase in speed and sensitivity when the body is warmed up. As a result, we respond more quickly and easily to movement changes.

Reduced Risk of Cardiovascular Irregularities. Abrupt physical exertion can cause arrhythmias and abnormal increases in blood pressure. Adaptation of coronary blood flow to sudden vigorous activity is not instantaneous; myocardial ischemia (lack of blood oxygen) can occur even in healthy, fit individuals (Barnard et al. 1973).

Appropriate Use of Energy Systems. A progressive, steady increase in activity allows the body to call on the appropriate energy systems to gradually move from rest to vigorous movement. If the workout begins too intensely (i.e., the porridge is too hot), the body is forced to rely heavily on anaerobic energy metabolism, causing a quick onset of lactic acid and fatigue. Conversely, a warm-up that begins too slowly without sufficient continuous movement (i.e., the porridge is too cold) delays all the processes that prepare the body for vigorous activity. But a gradual warm-up (i.e., the porridge is just right) allows us to work out more comfortably and for a longer period of time.

What to Avoid in a Warm-Up

Both static and single-joint dynamic stretches inhibit the rise in core-body temperature. Here’s why neither type belongs in an effective, efficient warm-up.

Static Stretches. At one time static stretches were an integral part of the warm-up because they were thought, by increasing flexibility, to decrease the risk of injury. However, convincing research demonstrates that static stretches performed during the warm-up do not prevent injury (Blair, Kohl & Goodyear 1987; Jacobs & Bornson 1986; Powell et al. 1986; Lally 1994). Rather, injury prevention is achieved by literally warming up the body.

As Daniel Kosich, PhD, stated in his 1999 World Fitness IDEA (WFI) convention session titled “The Flexibility Formula,” “Stretching prior to the aerobic part of the workout, in fact, isn’t even necessary. No evidence anywhere says you have to stretch prior to working out.” (For a more detailed description on why static stretches should be eliminated from your warm-ups, see “Wake Up Your Warm-Up” in the June 1996 issue of IDEA Today.)

Although flexibility remains an important component of fitness, the best time to focus on stretching is at the end of the workout, when tissues are at their warmest and more time can be devoted to each stretch. Len Kravitz, PhD, underscored this point in his 1999 WFI session “Current Controversies in Exercise”: “The best time physiologically for muscle elongation . . . (going to your end point and stretching) is postworkout. The warm-up is activity preparation.”

Single-Joint Dynamic Stretches. In the same way we once borrowed moves from dance and yoga, we later incorporated sports moves into our warm-up repertoire. If these moves had sports value, we reasoned, surely they would benefit our fitness participants. Additionally, we may have been seeking a substitute for static stretches once the message about needing to move became clearer. However, standing still to perform a single-joint action, such as ankle, neck or hip flexion, slows down and decreases the continuous warm-up effect. Ankle circles and spinal rotation may be common in sprinters’ or shot-putters’ warm-ups, but such moves don’t translate effectively to group exercise. Similarly, rolling the heel up and back in a staggered lunge may affect the calf but does little to activate major muscles. Once again, we need to stay focused on the goal of the warm-up—raising core temperature, not improving flexibility.

What to Include in a Cardio Warm-Up

So if static and single-joint dynamic stretches are out, what exactly is left? The active range warm-up consists of two phases: the rehearsal phase and the multijoint range-of-motion phase. Essentially, all movement is designed to prepare the body for the workload ahead. As multiple joints flex and extend, the major muscles are put through an active range of motion; as a result heart rate and core temperature continue to increase.

Rehearsal Phase. Rehearsal moves are a less intense version of the movement patterns participants will perform during the cardiovascular portion of class. These moves make up the majority of the active range warm-up, preparing participants mentally and physically for the challenges ahead. For example, if an upcoming cardio step combination includes a floor grapevine, two jumping jacks, and two basic steps on the other lead leg, the warm-up rehearsal might include a less intense version of these moves, in which the range of motion is slightly reduced (e.g, you might change the jumping jacks to step-touches).

Range-of-Motion Phase. Here’s where we get into the new, improved part of the warm-up. Like the rehearsal phase, this phase relies on rhythmic, continuous activities. The goal here, however, is to increase joint range of motion. To best accomplish this, you’ll want to select moves or movement sequences that require balance, challenge the core and put specific muscles through deliberate extension and contraction while maintaining core temperature. In practice, you may already be using such moves, but not emphasizing or recognizing their contribution to your warm-up goals. To maximize this contribution, you need to analyze your cardio choreography and mentally list specific joint actions that will be employed. A knee lift, for example, involves hip and knee flexion of the lifting leg. A rear lunge involves hip and knee extension of the lunging leg. For other examples, see “Typical Moves and Corresponding Joint Actions” below. Once you’ve analyzed the movements planned for the cardio portion of the workout, you’ll want to introduce their corresponding joint actions into the warm-up by combining several of these actions into one series to keep the body moving. For example, combining the knee lift and lunge joint actions creates a movement sequence appropriate for this phase of the warm-up (see “Range-of-Motion Phase: Kick/Lunge Series” on page 9). Another option is to perform “rocking horses” to challenge major muscles as they move through a large range of motion (see “Range-
of-Motion Phase: Rocking Horse Series” on this page). If later choreography requires hip extension, the warm-up could feature Charlestons (step left and kick the right leg forward, step right and touch the left leg back [hip flexion and extension]), with you cuing participants to really reach back with their rear leg.

Revised Warm-Ups in Action

Once we recognize the primary purpose of cardio warm-ups—to elevate core temperature in order to prepare the body to move—the decisions get easier. Any movements that conflict with or detract from the primary goal have no place in the warm-up.

What does belong in your warm-ups? First, time-efficient, targeted and timely movements that keep participants moving consistently and continuously. Second, two closely related phases that can be mixed and matched throughout and combined in any order. Third, moves that induce a light sweat and get heart rates poised at the lower end of the aerobic training zone by the end of the warm-up. While this may seem like a lot, you can achieve all these warm-up goals in seven to 10 minutes and be on your cardio way!

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