Supplementation of Kaempferia parviflora Extract Enhances Physical Fitness and Modulates Parameters of Heart Rate Variability in Adolescent Student-Athletes: A Randomized, Double-Blind, Placebo-Controlled Clinical Study.

2020-12-04
Journal of dietary supplements 19(2)
- Bungorn Sripanidkulchai
- Kreeta Promthep
- Sarunya Tuntiyasawasdikul
- Peera Tabboon
- Rosawan Areemit

PubMed: 33272042
DOI: 10.1080/19390211.2020.1852356

Study Design

Type: Randomized Controlled Trial (RCT)
Population: 194 male students
Methods: randomized double-blind controlled study, KP extract capsules at a dose of 360 mg/day and the control group received placebo capsules, continuously for 12 weeks
Blinding: Double-blind
Duration: 12 weeks

This randomized double-blind controlled study aimed to investigate the effects of a standardized Kaempferia parviflora (KP) extract on the physical fitness and heart rate variability (HRV) parameters in adolescent sport school students. 194 male students were recruited and randomized into two groups (n = 97), matched by age and sports. The KP-treated group received KP extract capsules at a dose of 360 mg/day and the control group received placebo capsules, continuously for 12 weeks. Physical fitness performance and HRV parameters were monitored with blood biochemical analysis for product safety. KP extract significantly increased the right-hand grip strength, the back-leg strength and maximal oxygen consumption (VO₂ max) and decreased the time used for 50-meter sprint test without changing the sit-and-reach test and the 40 yard technical test. For HRV parameters, KP extract significantly increased standard deviation of normal to normal intervals (SDNN), square root of the mean of square of successive normal to normal interval differences (RMSSD) and high frequency (HF) norm, without changing low frequency (LF) norm and LF/HF ratio. The increase in stress resistance and decrease in stress index were found in the KP-treated group, without changing the autonomic nervous system (ANS) activity and balance. Blood biochemical analysis showed normal values of all participants. This data indicates the safety and positive effects of KP on muscle strength, endurance and speed, but not on the flexibility and agility. The modulatory effects of KP extract on HRV parameters suggest its anti-stress effects and would encourage the application in a sport training and exercise.

Research Insights

Black Ginger→Changed Autonomic Nervous System Activity
without changing the autonomic nervous system (ANS) activity and balance
Effect
Neutral
Effect size
Small
Dose
360 mg/day
Black Ginger→Improved Agility
the 40 yard technical test
Effect
Neutral
Effect size
Small
Dose
360 mg/day
Black Ginger→Improved Autonomic Nervous System Activity
without changing the autonomic nervous system (ANS) activity and balance
Effect
Neutral
Effect size
Small
Dose
360 mg/day
Black Ginger→Improved Autonomic Nervous System Balance
without changing the autonomic nervous system (ANS) activity and balance
Effect
Neutral
Effect size
Small
Dose
360 mg/day
Black Ginger→Improved Flexibility
without changing the sit-and-reach test
Effect
Neutral
Effect size
Small
Dose
360 mg/day
Black Ginger→Increased Back-Leg Strength
the back-leg strength
Effect
Beneficial
Effect size
Small
Dose
360 mg/day
Black Ginger→Increased Grip Strength
KP extract significantly increased the right-hand grip strength
Effect
Beneficial
Effect size
Small
Dose
360 mg/day
Black Ginger→Increased Heart Rate Variability
KP extract significantly increased standard deviation of normal to normal intervals (SDNN), square root of the mean of square of successive normal to normal interval differences (RMSSD) and high frequency (HF) norm
Effect
Beneficial
Effect size
Small
Dose
360 mg/day
Black Ginger→Increased High Frequency Power
KP extract significantly increased high frequency (HF) norm
Effect
Beneficial
Effect size
Small
Dose
360 mg/day
Black Ginger→Increased Low Frequency Power
without changing low frequency (LF) norm
Effect
Neutral
Effect size
Small
Dose
360 mg/day
Black Ginger→Increased Maximal Oxygen Consumption
maximal oxygen consumption (VO2 max)
Effect
Beneficial
Effect size
Small
Dose
360 mg/day
Black Ginger→Increased Stress Resistance
The increase in stress resistance
Effect
Beneficial
Effect size
Small
Dose
360 mg/day
Black Ginger→Reduced 50-Meter Sprint Time
KP extract significantly decreased the time used for 50-meter sprint test
Effect
Beneficial
Effect size
Small
Dose
360 mg/day
Black Ginger→Reduced LF/HF Ratio
without changing LF/HF ratio
Effect
Neutral
Effect size
Small
Dose
360 mg/day
Black Ginger→Reduced Sprint Time
decreased the time used for 50-meter sprint test
Effect
Beneficial
Effect size
Small
Dose
360 mg/day
Black Ginger→Reduced Stress Index
decrease in stress index were found in the KP-treated group
Effect
Beneficial
Effect size
Small
Dose
360 mg/day

Adverse Events Reported

Black Ginger→Overall tolerability
Blood biochemical analysis showed normal values of all participants.
Finding
Reported