TO FATIGUE, OR NOT TO FATIGUE………THAT IS THE QUESTION

1

Jonathan Oliver, Ph.D., CSCS*D, USAWExercise & Sport Performance Laboratory, DirectorKinesiology DepartmentTexas Christian UniversityFort Worth, TX USA

Exercise & Sport Performance Laboratory

2

ACT AS IFSPECIFIC ADAPTION TO IMPOSED DEMANDS

SAID PRINCIPLE

TRAIN AS IF

Training Goal Load (%1RM)

Goal Repetitions

Sets Rest

Strength ≥ 85 ≤ 6 2-6 2-5 min

PowerSingle-effort eventMultiple-effort event

80-9075-85

1-23-5

3-53-5

2-5 min2-5 min

Hypertrophy 67-85 6-12 3-6 30 sec – 1.5 min

Muscular Endurance ≤ 67 ≥ 12 2-3 ≤ 30 sec

4

PastProgressive decline in maximum isometric force during repeated tetani

5

Velocity Declines When Repetitions Performed Continuously

Significant reduction in velocity when the number of repetitions was over ⅓ (34%) and ½ (48%) of the total number of repetitions performed for bench press and back squat, respectively

Izquierdo M, Gonzalez-Badillo JJ, Häkkinen K, Ibanez J, Kraemer WJ, Altadill A, Eslava J, and Gorostiaga EM. Effect of loading on unintentional lifting velocity declines during singles sets of repetitions to failure during upper and lower extremity muscle actions. Int J Sports Med 27: 718-724, 2005.

7

Near Linear Decrease

8

Lawton TW, Cronin JB, and Lindsell RP. Effect of interrepetition rest intervals on weight training repetition power output. J Strength Cond Res 20: 172-176, 2006.

PresentDecrease in power output, recognizes that fatigue can result from a reduction in either force or velocity

Debold EP. Recent insights into the molecular basis of muscular fatigue. Med Sci Sports Exerc 44: 1440-1452, 2012.

Allen DG, Lamb GD, and Westerblad H. Skeletal muscle fatigue: Cellular mechanisms. Physiol Rev 88: 287-332, 2008.

9

Causes of Fatigue• Acidosis

• Disassociation of hydrogen ions from lactate often associated with decrease in force

• Number of studies have demonstrated not the cause

• Inorganic phosphate (Pi)• Increases during contraction

mainly from breakdown of PCr

• Released in the transition from low force, weakly attached state, to high force state, strongly attached state

• Research limited

• Adenine diphosphate (ADP)• Increases during repeated

contractions coincident with PCr depletion

• Partial recovery of shortening velocity linked to removal of ADP by enzyme action or diffusion

• Experiments on skinned fibers show a major inhibitory effect on velocity of shortening

Debold EP. Recent insights into the molecular basis of muscular fatigue. Med Sci Sports Exerc 44: 1440-1452, 2012.

Allen DG, Lamb GD, and Westerblad H. Skeletal muscle fatigue: Cellular mechanisms. Physiol Rev 88: 287-332, 2008.

10

Time course of PCr resynthesis is fairly rapid

Harris RC, Edwards RHT, Hultman E, Nordesjo LO, Nylind B, and Sahlin K. The time course of phosphorylcreatine resynthesis during recovery of the quadriceps muscle in man. Pfluegers Arch 367: 137-142, 1976.

11

Hypothetical Model• Haff et al. (2003) presented first

hypothetical model in scientific literature

• Later suggested inclusion 15-30 second rest would allow partial replenishment of PCr

• Debate on the cause of fatigue still exists

• Current theories all suggest inclusion of 15-30 seconds rest would enhance the ability to maintain both

• Force• Velocity

Haff GG, Whitley A, McCoy LB, O'Bryant HS, Kilgore JL, Haff EE, Pierce K, and Stone MH. Effects of different set configurations on barbell velocity and displacement during a clean pull. J Strength Cond Res 17: 95-103, 2003.

Haff GG, Hobbs RT, Haff EE, Sands WA, Pierce KC, and Stone MH. Cluster training: A novel method for introducing training program variation. Strength Cond J 30: 67-76, 2008.

12

Inter-Repetition, Intra-Set, and Inter-Set Rest • Inter-set rest

• Rest between sets

• Inter-repetition rest (IRR)• Rest between repetitions within a given set

• Intra-set rest (ISR)• Rest between groups (clusters) of repetitions within a given set

Lawton T, Cronin J, Drinkwater E, Lindsell R, and Pyne D. The effect of continuous repetition training and intra-set rest training on bench press strength and power. J Sports Med Phys Fitness 44: 361-367, 2004.

13

Cluster Sets (CLU)Set which contains rest between the

individual repetitions (IRR) or groups of repetitions (ISR) contained within a set

Verkhoshansky Y and Siff M. Supertraining. Rome: Verkhoshansky, 2009.

Haff GG, Whitley A, McCoy LB, O'Bryant HS, Kilgore JL, HaffEE, Pierce K, and Stone MH. Effects of different set configurations on barbell velocity and displacement during a clean pull. J Strength Cond Res 17: 95-103, 2003.

14

Examples of Cluster Set Configurations

Rep 1 Rep 2 Rep 3 Rep 4 Rep 5 Rep 6

Rep 1 Rep 2 Rep 3 Rep 4 Rep 5 Rep 6

Rep 1 Rep 2 Rep 3 Rep 4 Rep 5 Rep 6

Rep 1 Rep 2 Rep 3 Rep 4 Rep 5 Rep 6

Traditional (TRD)

Cluster Sets (CLU)

2 min

2 min

2 min

2 min

X 4

X 4

X 4

X 4

15

= 15-30 second rest

PAST STUDIES

Acute Studies Suggested

•We could do more•We would be able

to generate greater power

•We could get stronger

Long Term Training Suggested

•We were able to do more

•We were less strong •We weren’t as

powerful

16

17

The Disconnect• Strength training

• ≥ 85% 1RM• EMG activity increases

linearly • Size principle

• Power training• Optimal load

• Load which optimizes power output

• 80% 1RM power clean• 40 – 60% 1RM bench

press• 50 – 70% 1RM back

squat

18

IN THE BEGINNING……• Resistance trained men (> 2 y)• 12 week periodized resistance training

program designed to elicit hypertrophy

• All exercises, exercise order, intensity, and volume were consistent between groups

• Critical to design as others have shown alterations in these variables to affect outcome

• Dietary intake, body composition, strength and power of upper and lower body musculature was measured at baseline, 4, 8 and 12 weeks

• Muscle biopsies for MHC were obtained at baseline (pre) and after 12 weeks of training (post)

THE PROGRAM

EQUATED TOTAL VOLUME LOAD PRODUCED SIMILAR LEAN MASS GAINS

AS BIG AS, STRONGER, FASTERWhen appropriately used, cluster sets superior

BUT WHY?No difference in myosin heavy chain composition following 12-week training

WHAT IS DRIVING THE GREATER POWER OUTPUT?WHAT IS DRIVING THE GREATER STENGTH GAIN?IS GREATER LOAD POSSIBLE?DO CHANGES IN FORCE AND VELOCITY CONTRIBUTE EQUALLY?WHAT IS CONTRIBUTING TO SIMILAR GAINS IN LEAN MASS?ARE THERE TRAINING AGE DIFFERENCES?

CLUSTERS…..THE SERIES

GREATER STRENGTH AND POWER LIKELY DRIVEN BY NEUROMUSCULAR FACTORS

Vastus Lateralis

Biceps Femoris

CLUSTERS ALLOW FOR GREATER TOTAL VOLUME LOAD

3100

3150

3200

3250

3300

3350

3400

3450

Kilo

gram

s

Total Volume Load

TRD

CLU*

AND VELOCITY DRIVES GREATER POWER OUTPUT

VBTSO CLUSTERS REALLY ARE

VELOCITY BASED TRAINING (VBT)

0

2

4

6

8

10

12

14

PRE SET1 SET2 SET3 IPE 5MIN 15MIN 30MIN

mmol•L

-1

LactateCLU

TRD

**

* *

*

*

LOWER TIME UNDER TENSION & METABOLIC STRESS, BUT….

DIFFERING IL-15 RESPONSE –ASSOCIATED WITH HYPERTROPHY?

Protein SynthesisMovement MechanicsBiofeedbackONGOING RESEARCH

FASTER STRONGERSAME MUSCLE MASS, BUT WHY?

PROTEIN SYNTHESIS• Resistance trained men (back squat

>1.5 body mass)

• Randomized

• Traditional (4 X 10) and

Cluster (4 X [2 X 5]) @ (~90%10RM)

• Infusion + biopsy

ALTERED MOVEMENT MECHANICS

POOR MOVEMENT PATTERNS

Movement Mechanics• Resistance trained men (back squat

>1.5 body mass)• Randomized• Traditional and Cluster (80%)• Back squat performed on bipedal force

platform (FP; AMTI, Watertown, MA) with retroreflective markers placed on the right and left ends of the barbell and thirty-three markers placed on the subject

• Kinetic and kinematic data• Hypotheses:

• Clusters will attenuate performance decrements (force, velocity, power)

• Clusters will attenuate altered movement mechanics

• Altered movement mechanics will be correlated with performance outcomes (force, velocity, power)

BiofeedbackVBT more accommodating to the daily fluctuations in muscle performance experienced by athletes

Mitigate against unwanted breakdown in movement patterns

Biofeedback considered a primary component of neuromuscular training (NMT)

Standard NMT utilizes verbal feedback

Internal Focus – less transfer of skill for complex movements required during sport

Biofeedback External Focus Superior movement patternsACL Injury Prevention

Methodologies

Familiarization SessionInformed Consent

Demographics

1RM TestingBack Squat

75% 1RMWith Target

(Peak) Velocity Biofeedback

90% 1RMWith Target

(Peak) Velocity Biofeedback

75% 1RMWithout

Biofeedback

90% 1RMWithout

Biofeedback

Kinetics, Kinematics, & Electromyography

48 Hours ≥72 Hours

as big asFASTERSTRONGERwhy train any other way? CONCLUSIONS

QUESTIONS