Edited by: Jackson Cioni Bittencourt, University of São Paulo, Brazil
Reviewed by: Akira Monji, Saga University, Japan; Sören Enge, Medical School Berlin, Germany
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The fall rate among adults 20–45 years old has reached 18% of the population and has gradually increased proportionally with age and has risen to 35% on 65 years old and above (Talbot et al.,
Our brief observation of OLS test in Rehabilitation Medicine Outpatient Clinic Dr. Soetomo General Academic Hospital on healthy people of 26–54 years showed 78% of 57 people had less than 50 s of OLS with their eyes closed. This showed a phenomenon of balance disturbance in a young and productive age that might contribute to the 18% fall in numbers as outlined above. Treadmill exercise is an aerobic training that is used to improve gait function; it also has two components (inclination and speed). Steib et al. (
Brain Derived Neurotropic Factor (BDNF) is essential for neuronal system, metabolism, peripheral and central homeostatic environment such as, regulating glucose oxidation, reduces blood glucose and increases insulin sensitivity (Knaepen et al.,
The aim of this study is to compare BDNF value before and after moderate-intensity treadmill with increased speed and increased inclination in untrained young healthy adult males. We hypothesized that there would be a significant rise of serum BDNF as an immediate and adaptive response after the moderate-intensity treadmill exercise with a gradually increased inclination and speed, and also there were significant differences in BDNF value between two groups.
The design of this study was a randomized pre- and post-test group. Twenty young healthy males were recruited in the study. The subjects were divided into two groups: inclination group (mean age 31.3 ± 3.04 years) and speed group (32.3 ± 2.31 years). Inclusion criteria were healthy adults according to WHO guidelines age within 26–37 years old with body mass index (BMI) 18–22.9 kg/m2 and signed the informed consent form. Participants were excluded if they had routine aerobic exercise at least two times per week, previous history of ischemic heart disease, restrictive/obstructive respiratory tract disease, and neuromusculoskeletal disease, systole blood pressure exceed 120 mmHg and diastole less than 60 mmHg, had vestibular and proprioceptive disturbance, and range of motion of both ankles for plantar flexion <45° and dorsiflexion <30°. This study was approved by ethical committee of Dr. Soetomo General Academic Hospital Surabaya Indonesia with ethical clearance no. 0206/KEPK/IV/2018.
Eligible subjects were asked to stand barefoot on the right limb and then left limb, with the other limb raised so that the raised foot was near but not touching the ankle of their stance limb. The subject was also asked to cross his arms over the chest and close their eyes. The investigator used a stopwatch to measure the amount of time the subject was able to stand on one limb. Time commenced when the subject raised their foot off the floor and ended when he used his arms, used the raised foot (moved it toward or away the standing limb or touched the floor), moved the weight-bearing foot to maintain his balance (rotated foot on the ground), a maximum of 50 s had elapsed. Time will be recorded.
Treadmill EN-Mill® 2007 were used as walking exercise devices. We utilized Polar H10 heartbeat sensors for the heart rate, installed to the participant’s chest and connected through blue-tooth to smart phones (as shown in
Inclination group participants using Polar H10 (Figure permissions had been approved by subject).
Blood samples were taken from all groups 30 min before the exercise, and 30 min after the exercise on the first and the last training program. Blood drawn and put in plain tube (without any activator) and kept in −80°C refrigerator. BDNF were measured using IBL Human BDNF ELISA kit Catalog no. BE69099 and Lot No. E30/2018J. The inclination groups were subjected to 3 km/h speed with gradual increase of the inclination starting from 2.5%, 5%, 7.5%, 10%, 12.5%, 15%, 17.5%, 20%, 22%. The inclination was increased every 1 min until the participant reached the target heart rate (70% maximum heart rate). The heart rates were recorded every minute, the inclination was raised. Speed groups started with 5 km/h and added 1 km/h every minute with 0% inclination until the participant reached the target heart rate (70% maximum heart rate; as shown in
Speed group participants using Polar H10 (Figure permissions had been approved by subject).
We observe the average value of BDNF, delta BDNF which show the difference of BDNF value pre- and post-exercise in each group. For statistic measurement, we used Kolmogorov–Smirnov for homogeneity test. The results were normal distribution, therefore authors used independent samples test to measure significance of each group and paired
This study was conducted for 2 weeks and included 20 young healthy males, and then all the participants were divided into two groups by randomized ballot. The participants were employees and residents medical doctors of Physical Medicine and Rehabilitation in Dr. Soetomo General Academic Hospital, Surabaya. Ten young men were grouped to utilize the inclination and 10 men for the speed. We presented the demographic data with normality test using independent samples test and exhibited normal distribution in both groups with
Demographic characteristic.
Groups | Mean | SD | |||
---|---|---|---|---|---|
Age (years) | Inclination | 10 | 31.33 | ±3.04 | 0.443 |
Speed | 10 | 32.30 | ±2.31 | ||
Body weight (kg) | Inclination | 10 | 64.11 | ±6.62 | 0.843 |
Speed | 10 | 64.80 | ±8.15 | ||
Height (cm) | Inclination | 10 | 169.22 | ±7.21 | 0.876 |
Speed | 10 | 168.70 | ±7.18 | ||
BMI (kg/m2) | Inclination | 10 | 22.20 | ±1.14 | 0.492 |
Speed | 10 | 22.64 | ±1.54 |
Normality test of CECAOLS in both groups before training.
Groups | Mean | SD | |||
---|---|---|---|---|---|
Closed eyes, crossed arms, | Inclination | 10 | 25.39 | ±12.11 | 0.338 |
Left, pre (s) | Speed | 10 | 34.44 | ±25.78 | |
Closed eyes, crossed arms, | Inclination | 10 | 18.97 | ±15.98 | 0.555 |
Right, pre (s) | Speed | 10 | 24.51 | ±23.02 |
In 2 weeks of exercise, the inclination group exhibited an escalating trend of BDNF serum, they exhibited an acute reduction of BDNF serum on the first day and only 18% escalation of BDNF serum after acute exercise on the final day. There was no significant increase of delta BDNF serum value in between the session from the first to the last day, and also the pre- and post-exercises from the first to the final day, with
Brain derived neurotropic factor (BDNF) serum result in inclination group.
The speed group exhibited a significant increase of BDNF serum with 111% escalation average. Comparing the BDNF serum of the pre-exercises from the first to the last day with
BDNF serum result in speed group.
There was significant escalation found in difference of pre-post exercie day 1 in inclination group compared to difference of pre-post exercise day 1 in speed group (
The difference of BDNF serum result in speed and inclination group.
In our study, we found there were significant negative correlations between CECAOLS before exercise with BDNF changes of the first day in speed group (
Correlation of CECAOLS and BDNF changes in both groups before and after training.
Speed | Inclination | ||||
---|---|---|---|---|---|
Δ BDNF | Δ BDNF | Δ BDNF | Δ BDNF | ||
exercise 1st day | exercise last day | exercise 1st day | exercise last day | ||
CECAOLS Pre-Exercise | D | ||||
S | |||||
CECAOLS Post-Exercise | D | ||||
S | |||||
Normal distribution of the demographic characteristics shows homogeneity of ages, weight, height, as well as BMI also showed the average CECAOLS value of participants in both groups using the independent sample test (
According to Karp, depending on the eccentricity and velocity of contracted muscles, some movement directly recruits fast-twitch muscle fiber. The recruitment of fast-twitch muscles depends on exercise intensity, variety, and goals (Karp,
In our study, within a particular time, there were changes of muscles recruitment from fast to slow-twitch muscle fiber that might cause the reduction of BDNF serum in 30 min after exercise in the first day. Walking inclined to the ground level forces the center of mass to displace the forward foot center, and at the same time, the gravity accelerated body to move forward. Momentum is also generated by trunk displacement of both legs (Leroux et al.,
BDNF are induced by many elements in body such as lactate, amount of Ca++, aerobic capacity, and also muscle fiber type used in exercising. Schiffer et al. (
Calcium intracellular activated CAMP Response Element Binding (CREB) will induce BDNF (West et al.,
In the speed group, there was no significant increase of BDNF serum intra-session from the first to the last day (
Ferris et al. (
At the first exercise in speed group, the low value of CECAOLS before exercise caused body compensation by increasing nerve activation which reflected by the BDNF value. In inclination group, there was positive correlation between CECAOLS and BDNF. The low value of CECAOLS led to small increasing of BDNF value, it was not significant. OLS was one of the balance measurement, treadmill exercise could be one of the balance exercise (Shimada et al.,
At the last exercise in inclination group, there were negative correlation between BDNF and CECAOLS. That is, low value of BDNF led to significant increase of CECAOLS of the right leg. In the speed group, there was also negative correlation between BDNF and CECAOLS. Low value of BDNF led to small changes of CECAOLS of the right leg. This showed inclination exercise will increase BDNF more efficient to achieve higher CECAOLS. McGeown et al. (
In speed group, there was negative correlation between BDNF and CECAOLS right leg pre-exercise that becomes positive correlation after exercise in the first day (Trend
Correlation of BDNF and CECAOL Dextra in Speed Group Pre Exercise First Day.
Correlation of BDNF and CECAOL Dextra in Speed Group Post Exercise First Day.
Correlation of BDNF and CECAOL Dextra in Speed Group Pre Exercise Last Day.
Correlation of BDNF and CECAOL Dextra in Speed Group Post Exercise Last Day.
In the inclination group, there was positive correlation between BDNF and CECAOLS right leg pre-exercise that become even more stronger positive correlation after exercise in the first day (Trend
Correlation of BDNF and CECAOL Dextra in Inclination Group Pre Exercise First Day.
Correlation of BDNF and CECAOL Dextra in Inclination Group Post Exercise First Day.
Correlation of BDNF and CECAOL Dextra in Inclination Group Pre Exercise Last Day.
Correlation of BDNF and CECAOL Dextra in Inclination Group Post Exercise Last Day.
Specific daily physical activities were not observed and might affect the BDNF serum objectively, it could be one of our confounding factors. Generalization of exercise is limited only in age characteristic, healthy adult male as hormonal factor can be a confounding factor. Therefore, we suggest further study in female subjects. The 30 min duration and 2 weeks intervention period of exercise did not show any significant escalation of BDNF serum in inclination group. For future study, longer duration and intervention period might be ideal to increase BDNF serum significantly using inclination treadmill.
There were significant increases in BDNF serum before and after 2 weeks moderate-intensity treadmill exercise with gradual speed escalation, however there was no significant increase of BDNF serum before and after treadmill exercise with gradual inclination escalation, and also there was significant difference of BDNF value between inclination and speed group for 2 weeks training in young healthy adult male with occult balance disturbance.
In the future, we suggest further study of occult balance disturbance. The treadmill exercise particularly with gradual speed increased are beneficial in developing BDNF serum with frequency three times per week in 2 weeks straight to young adult healthy male with occult balance disturbance. Also, the combination of speed and inclination treadmill exercise might enhance the serum BDNF.
This study was carried out in the accordance with recommendations of Balke and Athlete led protocols, Froelicher et al. (
All authors listed have made a substantial, direct and intellectual contribution to the work, and approved it for publication.
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
We thank all research subjects for all their dedication to every research condition.