Results

Table 1: Participant Characteristics (Mean ± SD)Male (n=33) Female (n=33)

Age (yrs) 36.82 ± 6.65 36.67 ± 5.37Height (cm) 178.54 ± 6.87 164.34 ± 6.56Weight (kg) 100.82 ± 13.46 88.10 ± 13.08BMI (kg/m2) 31.58 ± 4.09 32.48 ± 4.34%BF 31.13 ± 5.47 40.89 ± 6.61

PurposeTo evaluate the modulatory effects of sex on body composition and metabolism following eight weeks of HIIT and/or essential amino acid (EAA) supplementation in overweight and obese adults.

Indirect CalorimetryResting Metabolic Rate (RMR; kcal/day)

Substrate Metabolism (RER; a.u.) Carbohydrate vs. Fat Metabolism

Cardiorespiratory Fitness (VO2)

32

33

34

35

kg

FM

33

34

35

36

37

%

%BF

58

59

60

61

62

kg

FFM HIITEAAHIIT+EAACON

Figure 1: Body composition responses at baseline, 4wks, and 8wks when adjusted for baseline values. No significant interaction effect for sex between groups or across time for any variable (p>0.05).

-200.0-150.0-100.0-50.0

0.050.0

100.0150.0200.0250.0

ΔRM

R (k

cal/d

)

MALE

-0.10

-0.05

0.00

0.05

0.10

ΔR

ER (a

.u.)

* *

*

-200.0

-100.0

0.0

100.0

200.0

300.0

ΔRM

R (k

cal/d

)

FEMALE

-0.10

-0.05

0.00

0.05

0.10

ΔRER

(a.u

.)

HIITEAAHIIT+EAACON

*

Figure 3: Female metabolic change from 0-8 wksΔRMR ΔRER

HIIT 33.5 ± 40.4 -0.05 ± 0.02*

EAA -61.1 ± 46.8 -0.01 ± 0.02

HIIT+EAA 47.6 ± 45.5 -0.01 ± 0.02

CON 103.3 ± 62.7 0.01 ± 0.03

Figure 2: Male metabolic change from 0-8 wksΔRMR ΔRER

HIIT 133.9 ± 45.5* -0.03 ± 0.02

EAA 92.2 ± 39.0* -0.04 ± 0.02*

HIIT+EAA 51.6 ± 42.5 -0.03 ± 0.02

CON 55.1 ± 62.7 -0.02 ± 0.03

Katie R. Hirsch, Casey E. Greenwalt, Hannah E. Saylor, Courtney H. Harrison, Lacey M. Gould, Alyson G. Nelson, Dalton W. Wheeless, Gabrielle J. Brewer, Malia N.M. Blue, Abbie E. Smith-Ryan

• Paradoxical responses to moderate intensity exercise (i.e. gaining bodyfat) have previously been reported in women

• High-intensity interval training (HIIT) is an effective way to increasecardiorespiratory fitness and promote body composition changes in avariety of populations.

• Recent evidence in mice suggests that HIIT may overcome paradoxicalresponses, promoting positive changes in both men and women.

• Essential amino acids (EAA) support muscular and metabolic adaptationthrough the promotion of muscle protein turnover and increasing fatoxidation.

• HIIT, in combination with EAA, may create a metabolic environmentthat supports muscular adaptation.

Introduction

Experimental Design

• Despite no changes in body composition, HIIT improved RMR and fatoxidation in men and women, respectively. HIIT also improvedcardiorespiratory fitness in both men and women; adaptations may occurmore quickly in men, especially with EAA.

Conclusion

METABOLIC EFFECTS OF HIGH-INTENSITY INTERVAL TRAINING AND ESSENTIAL AMINO ACID SUPPLEMENTATION: MODULATORY EFFECTS OF SEX

Funded by a Doctoral Student Research Grantfrom the National Strength and ConditioningAssociation Foundation

Methods: all measurements completed at baseline, 4 weeks and 8 weeks

4-Compartment Body Composition ModelFat Mass (kg) = 2.748(BV) – 0.699(TBW) + 1.129(Mo) – 2.051(BM)

Percent Body Fat = (FM/BM) × 100

Fat-Free Mass (kg) = BM – FM

Mean changes adjusted for baseline values ± SE [95% CI]; *significant change from 0-8 wks based on 95% CI

2527293133353739

Base 4wk 8wk

VO

2 (m

l/kg/

min

)

A) Male: VO2adjusted means

22232425262728293031

Base 4wk 8wk

VO

2 (m

l/kg/

min

)

B) Female: VO2adjusted means

HIITEAAHIIT+EAACON

* §, $ #, §

Figure 4: Male (A) and female (B) cardiorespiratory fitness at baseline, 4wks, and 8wks. Values presentedare ANCOVA means adjusted for baseline values. *significant change from 0-4 weeks for HIIT+EAA;#significant change from 4-8 weeks for HIIT; §significant change from 0-8 weeks for HIIT andHIIT+EAA; $significant change from 0-8 weeks for EAA; significance based on adjusted mean change and95% CI.

RANDOMLY ASSIGNED TO 8-WEEKS OF:

2 days / week on cycle ergometer[6-10 × (1min @ 90%; 1min rest)]HIIT

Twice daily supplementation (7.2g EAA Daily)EAA

2 days / week on cycle ergometer+ Twice daily supplementationHIIT+EAA

No InterventionMaintained normal diet and exercise habitsCON

EAA Supplement

Practical Applications

HIIT is an EFFECTIVE and FEASIBLEapproach to increase

CARDIORESPIRATORY FITNESS and promote increases in

METABOLIC RATE and FAT OXIDATION in both MEN and

WOMEN

Twice daily EAA SUPPLEMENTATION

may also stimulate positive metabolic adaptations, increasing

METABOLIC RATE and FAT OXIDATION, independent of

exercise.

BV = Body Volume; TBW = total body water; Mo = Bone Mineral; BM = Body Mass