Analysis of the effects of different Freestyler tube
resistance levels on heart rate frequency and caloric expenditure


Independently published research paper by Tina Jarc Šifrar, MSc*, Maja Pori, PhD*, Primož Pori, PhD*
*University of Ljubljana, Faculty of Sport

Summary
Purpose of this research paper is to establish intensity of the workload and how test subjects react to different elastic resistances attached to all four limbs on the Freestyler workout platform in terms of absolute and relative heart rate frequency.

Eleven males and eleven females of Faculty of Sport in Ljubljana participated in this experiment. Set of variables included absolute and relative heart rate frequencies measured with "Polar Team System”.

For a precise description of the test subject sample (Calculation of V02max and maximum heart rate frequency), we used an intermittent Fitness test 30-15.

The results showed statistically significant increase in heart rate frequency of tested subjects.

We can conclude that Freestyler with different elastic resistance increased the efficiency of the test protocol in relative terms anywhere from 41 % to 86 % compared to no additional resistance.

caloric expenditure
60 min aproximation of caloric expenditure comparison between different resistance levels
(no resistance vs four different tube strength levels)

Introduction

Freestyler Fitness workout platform which was a subject of this study consists of a 120 cm long oval board with rollers at the each side through which 100 cm long elastic resistance tube is placed, providing constant full time elastic resistance attached to all four limbs (to arms attached by subject holding handles, to legs attached by the cuffs at the ankle height). Unique elastic tube placement and the configuration of the Freestyler board itself enables full three dimensional body movements in 360° executed in spiral and diagonal form, maximum range of motion adapted to each individual, synchronized whole body workout using upper and lower body while placing a substantial workload also on trunk muscles (core) by creating instability in the body by changing resistance pulls at each limb attachment. (Petrovic, et al., 2007)

Evidence in support of the elastic resistance used in training are provided by the Ozkaya and Nordin (1991), who investigated the change in length as a function of the applied force, the modulus of elasticity of the material, and the cross-sectional area, while several researchers have investigated electromyographic activity in muscles during elastic resistance exercise. (Cordova, Jutte and Hopkins 1999; Hintermeister, Bey, et al. 1998…)

Purpose of this research paper is to establish intensity of the workload and how test subjects react to different elastic resistances attached to all four limbs on the Freestyler workout platform in terms of absolute and relative heart rate frequency.


Methods

Participants
Eleven male (Age 23,4±1.1; Height 181,6±3,1; Weight 81,4±4,9; HRrest 50,5±4,7; HRmax 199,6±4,8; VO2max 51,82±2,4) and eleven female (Age 23,3±0,6; Height 169,8±3,8; Weight 59,5±6,3; HRrest 51,6±7,1; HRmax 195±8,2; VO2max 43, 8±2,8) of Faculty of Sport in Ljubljana participated in this experiment. All the students were in good health at the time when the tests were given and have personally volunteered to take part in this study.

Instruments
Set of variables included absolute and relative heart rate frequencies measured with "Polar Team System”. For a precise description of the test subject sample (Calculation of V02max and maximum heart rate frequency), we used an intermittent Fitness test 30-15 (Buchheit, Al Haddad H, Millet, Lepretre, Newton, & Ahmaidi, 2009).
Description of Fitness test 30-15 protocol

Marked out a 40m area with markers at either end and at the midpoint (20m). Placed markers 3 meters before each end line and either side of the mid-line (tolerance zones). The test involved 30 seconds of running alternated with 15 seconds of walking. Participants started behind one of the end lines, spaced from each other by one meter minimum.

They began to run on the first "beep”, pacing their effort to be in the area around the midline at the second "beep”, and then arrive at the opposite end at the third "beep”. This continues until there is a double beep, indicating the end of the 30 second period, and which point they stop running. This was not necessarily be at either end line. Tested subjects then walked forwards to the next line, waiting for the start of the next level in 15 seconds. As listed in Buchheit (2008), the initial velocity is 8.0 km/hr, with increments increased by 0.5 km/hr every 45-second stage thereafter. The test ended when the athlete does not make it into the tolerance zone three times.

The speed of the final phase completed in full is taken as the score (VIFT). Following formula was used to estimate VO2max based on the final running speed, where VIFT is the final running speed, G stands for gender (female = 2; male = 1), AG for age, and W for weight.(Buchheit et al. 2009)

VO2max (ml.kg-1.min-1) = 28.3 – (2.15 x G) – (0.741 x A) – (0.0357 x W) + (0.0586 x AG x VIFT) + (1.03 x VIFT)

Procedures
All test protocols conducted were the same in structure and movements used; only intensity of the workload was changed during 5 week period. Test protocol consisted of initial phase (warm up) 10 min, main phase 18 min and final phase (cool down) 10 mins.

Warm up phase of the workout consisted of cyclic moves usually used in the aerobic workouts (step touch, marching, V step, grapevine ...) in order to bring heart rate up and prepare subjects for the main part of the test.
Main part of the test protocol was constructed as a type of interval training using different muscle kinetic chains with 6 "multiplane whole body exercises” performed each for 3 minutes at given elastic outside resistance. Test subjects were performed one exercise and then move as quickly as possible to the next one.

Workload (main part)
Speed and intensity of the test was dictated by the 128 BPM music usually used for group fitness aerobic style workouts. Each of the moves used was repeated approximately 20 times per minute, totaling around 60 repetitions in 3 mins.

Selected multi plane whole body exercises were used in the main part of the test:
Exercise No.1: - step touch (alter. leg adductions) with alternating single arm multiaxis shoulder press
Exercise No.2: - reverse butterly (tubes crossed) with in between squat (90 degr. knee angle)
Exercise No.3: - squat (90 degree knee angle) into shoulder press (with forearm pronation)
Exercise No.4: - multiaxis walk (walk with knees high and biceps curl)
Exercise No.5: - cross country skiing upper body move with alternating leg abduction
Exercise No.6: - alternating hip extension with rotation in standing position with straight arms moving forward (palms in supinated position)

Experiment lasted for 6 weeks. In the first week we performed intermittent fitness test 30-15 to determine, measurements of resting heart rate and VO2max. In the next 5 weeks we exposed test subjects to the test protocol on the Freestyler workout platform.

Test was conducted in standardized conditions: i) test was taken same day of the week; ii) same time in the day; iii) before test 24 hour rest was assured.

In the second week, test protocol was performed without any outside elastic resistance. Third, fourth, fifth and the sixth week we increased intensity of the test by using different elastic tube strength levels from (Easy, Medium, Strong, Sport).

Tube strength level characteristics (Petrovic, et al., 2007):
Level EASY, tube length 100 cm, inner diameter 5 mm, outer diameter 9 mm
Level MEDIUM, tube length 100 cm, inner diameter 6 mm, outer diameter 10 mm
Level STRONG, tube length 100 cm, inner diameter 5 mm, outer diameter 10 mm
Level SPORT, tube length 100 cm, inner diameter 6 mm, outer diameter 11 mm

The acquired data was analyzed using the SPSS program, basic descriptive statistics was calculated. To identify differences between varying intensities of the test protocol produced by different tube strength levels, we used the method Repeated measures.


Results
Figure one shows the average absolute value of heart rate (beats / min) with different elastic resistance. Graph shows that the tested subjects reached average heart rate frequency values between 120 and 180 beats per minute, while men had slightly higher values in comparison to women . Heart rate frequency in the first training unit (without elastic resistance), on average peaked at 130 beats per minute in men and on average 125 times per minute in women group.

strongest elastic resistance
Figure 1: Average absolute value of heart rate frequency (beats/min)
with different elastic resistances

Average values of heart rate in the first training unit in comparison with other are relatively low and indicate a moderate aerobic workout intensity. Endurance type of training in the remaining four units, where we used different levels of elastic resistance, shows an increase in the average values of heart rate frequency, especially in the last two training units, where we used strongest elastic resistance.

Values of heart rate frequency in the last two training units have exceeded 180 beats per minute, where we take into account the fact that heart rate increases rapidly due to a combination of different resistance bands and movement structures, which include simultaneous workout of the upper and lower part of the body. The effectiveness of training in the last four training units (with elastic resistance) is produced by overcoming higher elastic resistance while Freestyler itself allows even load of all the major muscle groups of the body and consequently producing a substantial increase in muscle strength of the whole body.

Figure two shows the average relative value of heart rate frequency using different levels of elastic resistance. The average test subject values are ranging between 50% and 90% of maximum heart rate frequency. In the first training unit, which used no additional elastic resistance, test subjects achieved a relatively low average % of maximum heart rate, 55% of maxHR for men and 50 maxHR for women.

higher elastic resistance
Figure 2.: Average relative values of heart rate frequency (% of maxHR)
with different elastic resistances

In the remaining four training units, where an exercise intensity was increased by increasing elastic resistance, test subjects achieved an average of 70% to 90% of maximum heart rate. Given the fact that the greatest increase in aerobic capacity can be achieved if we practice at 60% to 80% of our maximum heart rate, we can conclude that type of exercise that involves varying degrees of elastic resistance is already very effective at the lowest tested resistance level. This fact is of great importance especially for beginners, since workouts must be safe and effective for beginners as well. By varying the level of elastic resistance, one can substantially increase aerobic capacity of the organism as well as increasing muscle strength and other motor skills that are crucial for improving the functionality of the body.


Discussion & Conclusion
The purpose of this study was to evaluate the potential increase in heart rate frequency by placing test subjects under different levels of elastic resistance on the Freestyler workout platform. The results showed statistically significant increase in heart rate frequency of tested subjects (20 students of Faculty of sport, 10 males, 10 females).

This study shows that even lowest elastic resistance (tube level easy) produces substantial increase in efficiency of the workout. Other three tube strength levels (medium, strong, sport) support this conclusion, increasing heart rate frequency in almost linear fashion with increased tube strength level. Heart rate frequency is strongly correlated with energy expenditure, which was also calculated based on different formulas applied (Keytel, L.R.; Goedecke, J.H.; Noakes, T.D. ; Hiiloskorpi, H. ; Laukkanen, R. ; van der Merwe, L.; Lambert, E.V., 2005).

Below graph explains the comparison between calories (kCal) between choosen test protocol (6 complex movements) without resistance and with resistance (4 elastic tube strength levels).

caloric expenditure
Figure 3: caloric expenditure comparison between different resistance levels
(no resistance vs four different tube strength levels)

We observed following substantial increase in caloric expenditure on the Freestyler with different levels of elastic resistance compared to no resistance:
- 29 % increase of caloric expenditure with tube strength "easy”
- 36 % increase of caloric expenditure with tube strength "medium”
- 42 % increase of caloric expenditure with tube strength "strong”
- 47 % increase of caloric expenditure with tube strength "sport”

We can conclude that Freestyler with different elastic resistance increased the efficiency of the test protocol in relative terms anywhere from 41 % to 86 % compared to no additional resistance.


References
Buchheit, Martin, March 2008, The 30-15 Intermittent Fitness Test: Accuracy for Individualizing Interval Training of Young Intermittent Sport Players, Journal of Strength and Conditioning Research: Volume 22 - Issue 2 - pp 365-374.
Buchheit M, Al Haddad H, Millet GP, Lepretre PM, Newton M, Ahmaidi S. Cardiorespiratory and cardiac autonomic responses to 30-15 intermittent fitness test in team sport players. J Strength Cond Res 2009; 23(1):93-100.
Keytel, L.R.; Goedecke, J.H.; Noakes, T.D. ; Hiiloskorpi, H. ; Laukkanen, R. ; van der Merwe, L.; Lambert, E.V., March, 2005, Prediction of energy expenditure from heart rate monitoring during submaximal exercise, Journal of Sports Sciences