HPRC & ACSM’s

High Intensity Training Conference and

Performance Optimization WorkshopSponsored by the

Human Performance Resource Center

September 13-14, 2010Uniformed Services University for the Health Sciences,

Bethesda, MD

Edward J. Zambraski PhD, FACSM

Division Chief, Military Performance Division

US Army Research Institute of Environmental Medicine (USARIEM)

Natick, MA

Baseline Fitness Requirements

Issues to be addressed

• What specifically do these commercial companies (e.g. CrossFit) say about baseline or minimal fitness requirements?

• Fitness requirements or other standards for circuit training in general?

• Risk factors for musculoskeletal injury?• Injury potential for individuals with low aerobic

fitness?• Army physical fitness standards/profile of the

average Soldier.

Options Offered by CrossFit.com Regarding Program Implementation

1. If you are largely familiar with the stable of CrossFit exercises then start with the WOD (Workout of the Day). This option is for those athletes with an extensive experience in athletic strength and conditioning

2. If some or many of the exercises are unfamiliar to you and you are only modestly acquainted with elite athletic training, we recommend that you follow the WOD and substitute other exercises for those where you don't have either the equipment or skill and then devise a plan for acquisition of the necessary skills or equipment needed to participate completely.

3. If many or most of the exercises are relatively or completely unknown to you, then we recommend that you begin learning the movements for a month or two until you can either perform our common exercises or have substitutions worked out for those movements under development.

• CrossFit workouts are extremely demanding and will tax the capacities of even the world's best athletes. You would be well advised to take on the WOD carefully, cautiously, and work first towards completing the workouts comfortably and consistently.

• The best results have come for those who've "gone through the motions" of the WOD by reducing recommended loads, reps, and sets while not endeavoring towards impressive times for a month before turning up the heat.

• We counsel you to establish consistency with the WOD before maximizing intensity.

www.crossfit.com

“You would be well advised to take on the WOD carefully, cautiously, and work first towards completing the workouts comfortably and consistently before "throwing" yourself at them 100%"

www.crossfit.com

“You would be well advised to take on the WOD carefully, cautiously, and work first towards completing the workouts comfortably and consistently before "throwing" yourself at them 100%"

CrossFit Training Guide[Copyright: 2006, page 5 (94 page document) ]

“CrossFit has tested its methods on sedentary, overweight, pathological, and elderly and found that these special populations met the same success as our stable of athletes.”

Fitness or other requirements for beginning an activity or circuit training

program.

ACSM guidelines for participation screening such as the PAR-Q (Physical Activity Readiness Questionnaire) and/or the ACSM risk stratification for screening and medical supervision.

Risk Factors for Muscle Injury

• Prior Injury• Being “untrained” (low aerobic fitness)• Unaccustomed exercise• Gender (female)• Smoking• High BMI• Too little or too much flexibility• “Over Training” (running mileage)

(Data from USARIEM, Injury Epidemiology (TAIHOD) )

Association of First Two-Mile Run With Time-Loss Injuries in BCT

10

30

50

70

Q1(fast) Q2 Q3 Q4(slow)Quartiles of Two-Mile Run Times

Inju

ry I

ncid

ence

(%

)

MenWomen39

5559

N=684 Men, 381 Women; Risk Ratio(Q4/Q1):Men=1.4,Women=1.6p-value for Trend: Men=0.03, Women=<0.01Knapik, USACHPPM Epicon Report No 29-HE-8370-99, 1999

61

2123

32 30

Variability in Fitness/Work CapacitySummary of Studies in Basic Combat Training

Parameter Value Coefficient of Variation

Strength Measures --- 14 - 28

VO2max Males 50 ± 6 mL/kg/min 12

Females 39 ± 5 mL/Kg/min 12

Two Mile Run Time (min) Males 15 - 17 ± 2-3 16

Females 20 - 21 ± 3 14

One Mile Run Time (min) Males 8.4 ± 1.3 15

Females 10.3 ± 1.3 20

Body Weight (kg) Males 79.3 ± 13 (N = 404) 16

Females 63.5 ± 8 (N = 143) 12

% Body Fat Males 18.7 ± 4.8 25

Females 30.7 ± 6.3 20

SummaryThere is an apparent lack of concern about those entering these programs who may have a low level of fitness, strength, and/or other risk factors. “One size fits all.”

Those with low aerobic fitness/strength are particularly vulnerable to musculoskeletal injury; even with moderate intensity exercise programs.

Comment on “injury” is essentially totally absent.

The military population represents the full array of fitness/strength levels; they are all not elite athletes.

Musculoskeletal injuries within the Army are the major cause for medical disability discharge, lost duty time and medical costs.