Exercise Physiology Paul M. Vanderburgh, EdD, FACSM Professor and Chair, Health and Sport Science Department University of Dayton, Dayton, Ohio

Optimizing Athletic Performance

Fitness Body Composition Cardiorespiratory Endurance Muscular Strength/Endurance

Environmental Physiology

Occupational Physiology

Exercise Epidemiology CHDNIDDMStrokeCancer

Exercise Biochemistry NutritionSupplements Weight Loss/Gain

Fitness Focus C-R Endurance Musculoskeletal Strength/Endurance

Cardiorespiratory Endurance Defined by VO 2max : the maximum rate of oxygen consumption = HR x SV x a-v O 2 difference at max Determinants –Training (myoglobin content, myochondrial # and density, SV, capillary density) –Fiber type distribution Gold standard: open circuit spirometry Typically estimated by distance run tests Expressed as ml O 2 per kg per min

Muscle Strength/Endurance Defined by maximum force generated by muscle group once or multiple times Determinants: –Training (Muscle CSA, glycolytic capacity, neuromuscular adaptations) –Fiber type distribution –Biomechanical advantage Gold Standard: Isokinetic dynamometry Typically estimated by 1RM or REPS of body weight (e.g., push-ups) Expressed as lbs or ft. lbs

Body Mass Bias and Occupational Relevance of Military Physical Fitness Tests Paul M. Vanderburgh, EdD, FACSM Professor and Chair, Health and Sport Science Department University of Dayton, Dayton, Ohio Presented at the American College of Sports Medicine’s 2007 Annual Meeting, New Orleans Published in Medicine and Science in Sports and Exercise, 40(8): , 2008

How Military Fitness is Assessed (Army, Air Force, Navy) Sit-ups or Curl-ups Push-upsDistance Run

Military Physical Fitness Tests Conducive to mass testing No special equipment needed Body weight is the primary resistance

Typical Physically Demanding Military Tasks Light Load Carriage Heavy Load Carriage Heavy Handling

Light Load Carriage

Heavy Load Carriage

Body Mass Bias

Body Mass Bias 101 Defined as the non-zero correlation between body mass and a physical performance measure –Push-ups, sit-ups –Distance run –1RM strength Free of the confounding effects of effort, body fat, or physical activity level Theoretical basis

Scale Modeling of Body Mass Bias A 25% increase in mass (exact replica): 1RM bench press is 16.0% greater VO 2max (L/min) is 16.0% greater Run Time is 7.7% slower Push-ups and Sit-ups Reps are 7.2% fewer

Example – 5K Run Crecelius JSCR (in press)

Comparison of Runners B is 8.5% slower than A A B

Comparison considering body mass Distance from the best-fit curve B is 8.6% faster than A A B

Body Mass Bias Example Powerlifting TOTAL (data from IPF website: 5/07)

TOTAL per M Ratio Method

TOT per M 2/3

Body Mass (M) and Strength Theory Strength α muscle CSA Muscle CSA α M 2/3 Therefore strength α M 2/3 Fair comparison: 1RM/M 2/3 (Astrand & Rodahl, Textbook of Work Physiology ’86)

M Bias and Strength Evidence MeasureSubjectsNExponentsSource Powerlifting Elite Women Elite Women 36 world record holders 36 world record holders Vanderburgh MSSE ‘00 Powerlifting Elite Men 30 world record holders 0.49 – 0.68 Dooman JSCR ‘00 Olympic Lifting Elite M & W * Batterham, JAP ‘97 Bench Press M college-age PE students Markovic EJAP ‘04 Leg Strength Young M & W Jaric JSMPF ‘02 Exponents are somewhat variable Not all confidence intervals contain 0.67 but none contain 1.0 or 0 *Found simple allometric model problematic

Body Mass and VO 2max Theory VO 2max (L) α M Time α M 1/3 VO 2max (L/min) α M/M 1/3 Therefore VO 2max (L/min) α M 2/3 Fair index: ml O 2 /(kg 2/3. min) (Astrand & Rodahl Textbook of Work Physiology ’86)

Body Mass and VO 2max Evidence SubjectsN M Exponent Source Young W (LBM exp = 1.04) Vanderburgh MSSE ‘96 M, yr 1, * (LBM exp = 0.97) Batterham, JAP ‘99 Young fit M & W Nevill EJAP ‘92 M & W, yr ** Heil MSSE ‘97 *Found the simple allometric model problematic **Controlling for age, gender, %fat and SR-PA score

Body Mass and Distance Run Time (RT) Theory 5K run speed (RS) α VO 2max (ml/kg. min) But VO 2max (L/min) α M 2/3 So RS α M 2/3 /M or RS α M/ -1/3 Given that RT α RS -1 RT α M 1/3 Fair index: RT/M 1/3 (Nevill JAP ’92, Vanderburgh MPEES ‘07)

Body Mass and Distance Run Time (RT) Evidence MeasureSubjectsNExponentsSource 2-mile RT M USMA cadets (FFW exp. = 0.31) Vanderburgh JSCR ‘95 2-mile RT M USMA cadets (LBM exp = 0.24) Crowder MSSE (abstract ’96) 5K Run Young fit M & W * Nevill EJAP ‘92 5K Run 5K M Runners ** Crecelius MSSE ’07 (abstract) Exponents not diff. from 0.33 but diff. from 0 *Indirectly calculated from: run speed = f(VO 2max, body mass) equation **calculated using subjects with RPE > 16

Body Mass and Push-ups/Sit-ups REPS Theory Muscle force α M 2/3 REPS α M 2/3 /M or M -1/3 Push-up, Sit-up REPS α M -1/3 Fair index: REPS. M 1/3 (Markovic EJAP ‘04)

Body Mass and Push-ups/Sit-ups REPS Evidence MeasureSubjectsNExponentsSource Push-ups M USMA cadets (LBM exp = -0.28) Crowder MSSE (abstract ’96) Sit-ups M USMA cadets (LBM exp = -0.24)* Crowder MSSE (abstract ’96) Push-ups M college-age PE students Markovic EJAP ’04 Push-ups M college-age PE students Markovic EJAP ’04 Only exponent diff. from and only slightly No studies on women

Body Mass Bias Conclusions for Military Physical Fitness Tests Military physical fitness test events favor lighter individuals, independent of body fatness Distance Run –RT α M 1/3 –Fair index = RT/T 1/3 Push-up, Sit-ups –REPS α M -1/3 –Fair index = REPS. M 1/3

Occupational Relevance

Heavy Handling

Free Carry and Stretcher Carry Performance Strongest correlates of free carry and stretcher carry performance: –High LBM to dead mass (FM + plus casualty mass) ratio –Standing broad jump –Upright pull (Bilzon Occup Med ‘02)

Load Carriage Determinants Time to exhaustion on 18kg Load Carriage (LC) test was: –Not correlated with relative VO 2max –Positively correlated with LBM Simplified aerobic physical fitness tests (e.g., 2.4 km run) did not predict ability to perform LC tasks (Bilzon Occup Med ‘01)

Absolute VO 2max and LBM/DM were the most potent predictors of %VO 2max during heavy (40 kg) LC tasks Absolute VO 2max, LBM/DM, gradient, and load accounted for 89% of variance in %VO 2max (Lyons Occup Med ’05) Load Carriage Determinants

PF Tests as Predictors of Military Performance Body size, muscle strength, and aerobic fitness (L/min) differentially predicted lifting and load carriage task performance –Not push-ups –Sit-ups generally weak –Relative VO 2max only for light load carriage (Rayson Ergonomics ‘00)

PU, SU, 2MR Military Task Performance, 18 kg loaded 30m sprint to and from prone position –Vertical jump and 2MR 400M sprint –2MR and vertical jump Obstacle course –Long jump, SU, vertical jump Casualty recovery –Body mass, vertical jump, and 2MR (Harman Mil Med (2008)

Occupational Relevance and Physical Fitness Tests Conclusions Military physical fitness test performance is generally not a potent predictor of loaded task performance LBM, LBM/DM, upright pull, 1RM lift, and absolute VO 2max are more predictive of load carriage performance

Run Time, Effort and %Fat Age & Wt 5K Handicap Model –Penalty for fat > credit for extra weight (Vanderburgh MPEES ’07) –With RT/M 1/3, small remaining bias is accounted for by RPE and % fat [Crecelius JSCR (in press)]

The Evidence Suggests: Military Physical Fitness Tests 1.Are not potent indicators of performance of typical, loaded military tasks 2.Impose a systematic bias against larger, not fatter, service members 3.1. and 2. are interrelated Solutions 1.Scaled Values 2.Correction Factors 3.Balanced Fitness Tests (validation needed)

Implications/Solutions

Body Mass Bias Penalty - Navy (Vanderburgh, Mil Med, 2006)

Body Mass Bias and Occupational Relevance Connection The more potent predictors of loaded military task performance (LBM, LBM/DM, upright pull, 1RM lift, and absolute VO 2max ) tend to favor heavier individuals (LBM, LBM/DM, upright pull, 1RM lift, and absolute VO 2max ) Empirical and theoretical evidence suggests that common physical fitness test events favor lighter individuals Middle ground?

Occupational Relevance and Body Mass Bias BW Resistance Only Fixed W Resistance Only Heavy equipment or supplies lifting/carriage Light load carriage over distance Heavy load carriage over distance P’ups, S’ups, Distance Runs Most physical military tasks Fitness tests

Backpack Run Test (Vanderburgh Mil Med ’00) 59 USMA male cadets –Lean, fit –Two-mile run times Modeled effects of alterations in backpack weight (BW) via ACSM equations on two-mile run times Backpack weights of kg: –No body mass bias –Reflected load carriage weights expected of combat support and/or combat arms service members Eliminating bias may be congruent with occupational relevance

Solution 1: Scaled Values Requires calculator Creates strange currency SubjectPush-ups Body Mass REPS. M 1/3 A67 80 kg B70 68 kg 281.7

Solution 2: Correction Factors Correction Factor (CF) : a dimensionless number multiplied by raw score –Based on body mass –Uses weight standard (e.g., 50 kg) Example: woman, 172 lbs, 16:08 RT –CF = (125/172) 1/3 = 0.90 –RTadj = 14:31 (Vanderburgh Mil Med ’07)

Correction Factors Push-ups and Sit-ups (Vanderburgh Mil Med ‘07)

Correction Factors – Effect (Vanderburgh Mil Med ‘07)

Solution 3: Balanced Tests Balance of body mass bias via events. Example: –1RM Bench press –Distance run time Logistics challenges Has not been empirically evaluated

2005 Pump and Run 5K run time minus (30 x Bench Press Reps) = adjusted score Bench Press weight a % of BW and age-adjusted Despite intent, imposes a substantial body mass bias Proposal: correction factors or everyone lifts the same absolute weight (Vanderburgh JSCR 2008)

Marine Corps Combat Fitness Proposed Combat Fitness Test Events and Data Collection Plan

–880 yd Run Conducted like 3 mile run Testing will determine best sequencing and numbers of Marines in each “heat” if not mass start –Ammo Lift Marines matched up as in crunches Will test two versions in data collection period See pictures –Maneuver Under Fire Will test two versions in data collection period May be modulated See diagrams Proposed Events

880 Yd Run

AMMO LIFT Marine lifts 30 lb ammo can as many times in determined time period (1 min-1 ½ min- 2 min versions will be tested) StartMid-Lift Finish Weight on Heels Weight on Heels Lumbar curve maintained throughout lift Feet Shoulder Width Apart Ammo Can at or below chin level Arms straight at finish Heels may rise at finish Ammo can does not have to be directly overhead at finish

DIAGRAM NOT TO SCALE: ALL LEGS OF EVENT OCCUR WITHIN ONE LANE ( APPROX 8 YDS WIDE) Notes: Grenade Throw: -Target area 5 yd x 5yd marked w/ engineer tape -Center of target area 22 ½ yds from 75 yd line -”Hit” if throw lands in target area or on border. -Hit=10 sec deduction from time/Miss=10 sec addition to time Cone network: -5 yds apart in width/length beginning at 50 yd line -Marines negotiate all or portion of the same network on all legs of event. CASEVAC -Marines paired by approximate weight Equipment needed: -30 lb ammo cans, Field lining materials, Dummy grenades, kneepads, stopwatch and cones, sandbags or other markers. Leg 1: - Start in prone position -”Ready, Go” -25 yd Sprint-25 yd Modified High Crawl (hands and knees)-25 yd Diagonal Run -Pick up casualty in Cradle Drop (underarm carry position) Leg 2: -Drag casualty 10 yds through last two cones of network w/ start line as reference. Once casualty in carry position, bottom of feet may not touch ground -Transition casualty to Fireman’s Carry (casualty may assist rescuer) -65 yd Fireman’s Carry to start--Place casualty on ground -Pick up two (2) 30 lb ammo cans Leg 3: -50 yd Sprint w/ammo cans-25 yd Diagonal Run w/ammo cans -Ground ammo cans -Engage grenade target from standing position, take cover momentarily in prone position with hands covering head Leg 4: -Rise to standing position, pick up ammo cans -25 yd diagonal run-50 yd Sprint to Finish = Cone, sandbag or other marker “MANEUVER UNDER FIRE (300 yds)” 25 yds 50 yds 75 yds 100 yds Leg 1 Leg 2Leg 4 Leg 3 Finish Grenade target area Start “Casualty” in seated position w/ back towards start line Sprint Mod. High Crawl Diag. Run Ammo Carry Ammo Carry Grenade Throw Drag Fireman’s Carry Monitor (can grade two target areas at once. Field monitor supports.) Field Monitor (follows Marine through course beginning at 25 yd line on Leg 1) Start/Finish Monitors-Rotates with Field Monitor as necessary

Conclusions Current physical fitness tests of the Army, Navy, and Air Force: –Are not potent determinants of physical military task performance –Impose a physiological bias against heavier service members Eliminating body mass bias may be more occupationally relevant – must be tested empirically Solutions –Scaled values require no change to fitness test protocol but create strange currency –Correction factors provide ease of calculation, preservation of original units, and require no equipment –Balanced fitness tests require equipment but no calculations – need validation

Questions?