High-Intensity Interval Training and Performance

Study Overview
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Brief Summary
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The goal of this clinical trial was to compare to different types of high-intensity interval training in young, healthy females. The main questions were: Will changes in body composition differ between the two interventions? Will changes in endurance and muscle performance differ between the two interventions? Participants were randomized to 8 weeks of high-intensity interval training involving body weight, plyometric exercises or cycling only. Researchers compared changes in endurance performance, body composition, and muscle performance to determine if there were differences between groups.

Detailed Description
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The purpose of this study was to compare the effects of plyometric- and cycle-oriented high-intensity interval training on body composition, aerobic capacity, and skeletal muscle size, quality, and function in recreationally trained females. Young (21.7 ± 3.1 yrs), recreationally active females were randomly assigned to 8 weeks of twice weekly plyometric (n = 15) or cycling (n = 15) high-intensity interval training. The plyometric-oriented Les Mills BODYATTACK program was used for the plyometric group whereas Les Mills SPRINT, which exclusively involves stationary cycling, represented the cycling group. Both protocols involved alternating high-intensity and recovery intervals, and participants were consistently instructed to give maximal effort during the 'work' periods. The 30 min plyometric routines included four blocks of high-intensity exercise intervals. The 'work' portions consisted of the following exercises: high-knee runs, plyometric lunges, jumping jacks, squat jumps, burpees, and speed-agility patterns. The recovery periods consisted of complete rest (transitioning between exercises), a light jog, or a low impact stepping motion. On average, participants were instructed to give maximal effort for 1-2 min, with recovery intervals of 15-45 sec. Four separate routines were used throughout the duration of the study, keeping one routine per week; participants completed each routine a total of 4 times within a session. The 30 min cycling routines were performed on upright stationary bikes (Schwinn, AC Performance, Chicago, IL). Protocols involved 'work' ranging from 20-80 sec with recovery intervals between 10-60 sec. Recovery intervals consisted of complete rest on bike or particularly slow cycling. Resistance and cycling speed were relatively variable across sessions, with some intervals of higher resistance and lower speed and others involving lower resistance and higher speed (e.g., >120 RPMs). The same four workouts were used throughout the duration of the study alternating each week. Body composition (4-compartment model), VO2peak, countermovement jump performance, muscle size and echo intensity (muscle quality) as well as strength and power of the knee extensors and plantar flexors were measured before and after training. Body composition testing was completing using dual-energy x-ray absorpiometry, air displacement plethysmogrphay, and bioeletrical impedance. VO2peak was measured using a standardized maximal exercise test on a treadmill. Countermovement jump height and power was recorded with participants performing jumps on a force plate. Muscle size and quality were determined using non-invasive ultrasonography. Finally, serum growth hormone responses to the VO2peak test were measured before and after the protocols.

Official Title
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Effects of Plyometric- and Cycle-Based High-Intensity Interval Training on Body Composition, Aerobic Capacity, and Muscle Function in Young Females: a Field-based Group Fitness Assessment

Conditions
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Healthy

Intervention / Treatment
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* Behavioral: High-Intensity Interval Training


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Between 18-35 years of age Female Currently participating in 2-4 days of structured exercise for 30-75 minutes for the last 6 months Exclusion Criteria: Currently participating in these exercise formats (2x/week within last 3 months) Engaging in high intensity interval training for more than 30 min/week Have diagnosed disorders/diseases in the following: cardiovascular, pulmonary, immunological, or metabolic Current musculoskeletal injuries Pregnant or think you may be pregnant Currently taking any non-steroidal anti-inflammatory drug(s) or steroidal drug(s) Currently a smoker or has consistently smoked within the last year Has a positive written or verbal pre-study drug screen including alcohol (more than 7 drinks/week), THC/cannabinoids, amphetamines, benzodiazepines, cocaine, opioids, phencyclidine, barbiturates, cotinine. Currently taking any medication that will significantly affect your heart rate response to exercise If you miss four or more classes, you will be excluded from the study

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Two groups performed different types of high-intensity interval training
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Plyometric High-Intensity Interval Training<br>This group performed high-intensity interval training consisting of body-weight, plyometric exercises involving jumping. | Behavioral: High-Intensity Interval Training<br>* The training intervention is a popular exercise format that consist of alternating brief bouts of high-intensity efforts with bouts of light effort or complete rest.<br>|
| Experimental: Cycling High-Intensity Interval Training<br>This group performed high-intensity interval training consisting of cycling exercise. | Behavioral: High-Intensity Interval Training<br>* The training intervention is a popular exercise format that consist of alternating brief bouts of high-intensity efforts with bouts of light effort or complete rest.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Muscle composition at baseline | echo-intensity value derived from ultrasound that indicates the amount of fat infiltration in muscle | Pre-intervention | 
| Muscle composition after 8-week intervention | echo-intensity value derived from ultrasound that indicates the amount of fat infiltration in muscle | At week 9 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Fat mass at baseline | Amount of fat tissue a person possesses | Pre-intervention | 
| Fat mass after 8-week intervention | Amount of fat tissue a person possesses | At week 9 | 
| Group average growth hormone response (concentration at microLiters/Liters) at baseline | The acute, exercise-induced response for growth hormone | Pre-intervention | 
| Group average growth hormone response (concentration at microLiters/Liters) after 8-week intervention | The acute, exercise-induced response for growth hormone | At week 9 | 
| Countermovement jump height at baseline | Height of jump | Pre-intervention | 
| Countermovement jump height after 8-week intervention | Height of jump | At week 9 | 
| Time to peak torque at baseline | How quickly muscle torque is generated | Pre-intervention | 
| Time to peak torque after 8-week intervention | How quickly muscle torque is generated | At week 9 | 
| Maximal oxygen consumption at baseline | Standard measure of maximal oxygen consumption or peak aerobic capacity during exercise | Pre-intervention | 
| Maximal oxygen consumption after 8-week intervention | Standard measure of maximal oxygen consumption or peak aerobic capacity during exercise | At week 9 | 
| Body fat percentage at baseline | Relative amount of body fat a person possesses | Pre-intervention | 
| Body fat percentage after 8-week intervention | Relative amount of body fat a person possesses | At week 9 | 
| Fat-free mass at baseline | Amount of non-fat tissue a person possesses | Pre-intervention | 
| Fat-free mass after 8-week intervention | Amount of non-fat tissue a person possesses | At week 9 | 
| Peak torque at baseline | Strength of a muscle | Pre-intervention | 
| Peak torque after 8-week intervention | Strength of a muscle | At week 9 | 
| Muscle cross-sectional area at baseline | The size of a muscle | Pre-intervention | 
| Muscle cross-sectional area after 8-week intervention | The size of a muscle | At week 9 | 
| Muscle power at baseline | Product of torque and velocity as determined on a dynamometer | Pre-intervention | 
| Muscle power after 8-week intervention | Product of torque and velocity as determined on a dynamometer | At week 9 |