EQOL Journal (2019) 11(1):
ORIGINAL ARTICLE
Influence of inertial resistance squat exercise protocol based on novel exercise intensity determination on physical fitness of older adult women
Darjan Spudić 1 ✉ • Vedran Hadžić 1 • Janez Vodičar 1 • Jamie Carruthers 2 • Primož Pori 1
Received: 28th March, 2019 |
DOI: 10.31382/eqol.190604 |
Accepted: 19th May, 2019 |
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© The Author(s) 2019. This article is published with open access. |
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Abstract
The aim of the study was to examine practical implications and actual effects of the
11)and to two exercise – inertial (n = 12) and traditional (n = 14) – groups.
The participants performed hip belt squats on the inertial device and kettlebell squats, respectively. Exercise intensity was relatively adjusted using mass moment of inertia (MMI) of the cylindrical weight and %1RM. Time under tension was equalized between groups by the type of the exercise executed. Tests were performed before and after the intervention. Moreover, RPE was monitored after each exercise set. We used
The Senior Fitness Test results significantly differed in pre and post measurements, regardless of
✉
1University of Ljubljana, Faculty of Sport, Ljubljana, Slovenia
2Wakefield University Centre, Wakefield, United Kingdom
the group. A significant time x group interaction was only found in
The results indicate that inertial resistance exercise using the novel exercise intensity determination on the inertial device is a useful and less strenuous alternative to traditional resistance exercise among older adult women while performing squats.
Keywords inertia • sarcopenia •
Introduction
Processes of aging, of which the leading factor is sarcopenia, cause on the one hand decreased physical and functional abilities (Narici & Maganaris, 2006), whereas on the other hand they cause the increase in getting some
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EQOL Journal (2019) 11(1):
2000) which was also discovered in some studies concerning inertial devices (Onambele, Maganaris, Mian, Tam, Rejc, McEwan, & Narici, 2008).
Inertial load presents a new trend in resistance exercise possibilities. The effects of this type of resistance exercise on muscle hypertrophy and strength were shown to be more “robust” than those gained from weightlifting protocols (Petré, Wernstål,
&Mattsson, 2018). In contrast to weightlifting, the angular momentum (AM) of a wheel, which is created in the concentric part of a muscle contraction on an inertial device, causes episodes of increased muscle activation and produces higher mechanical forces in the eccentric part of contraction (approximately 25% compared to the concentric part). This phenomenom is known as “eccentric overload” (Norrbrand, Pozzo,
&Tesch, 2010).
Numerous studies have established that eccentric contractions can maximize the force exerted and the work performed by muscles, are associated with a greater mechanical efficiency, can attenuate the mechanical effects of impact forces, and enhance the tissue damage associated with exercise. The neural commands controlling eccentric contractions are unique. Eccentric contractions require lower levels of voluntary activation by the nervous system to achieve a given muscle force due to differences involving recruitment order, discharge rate and recruitment threshold of motor units in comparison to concentric contractions. A common
Firstly, the purpose of this research was to examine a progressive resistance exercise protocol using a
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exercise intensity determination. Furthermore, the purpose of the research was to examine the effects of the inertial device exercise protocol compared to the traditional
Method
The research included 44 healthy older adult women
Procedure and equipment
Before the exercise program, the participants were asked to fill in the
EQOL Journal (2019) 11(1):
Table 1. Basic characteristics of the study participants; values are Mean±SD
|
Control |
Traditional |
Inertial |
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(N= 11) |
(N=14) |
(N=12) |
|
|
|
|
Variable |
Mean±SD |
Mean±SD |
Mean±SD |
|
|
|
|
Age (years) |
67.3±4.5 |
71.6±6.4 |
68.8±6.4 |
BMI (kg/m2) |
29.9±5.3 |
25.6±4.7 |
24.8±4.1 |
Exercise intervention
Throughout eight weeks of resistance protocol the participants performed hip belt squats (Figure 1) as a part of the standardized exercise unit. In the group executing inertial exercise the
exercise intensity using mass moment of inertia (MMI) of the cylindrical weight. In the group that carried out the traditional exercise, kettlebell weights were used that were held with both hands and adducted between the thighs while performing a squat.
Figure 1. Training belt for attaching the load to the pelvis
Table 2 presents the progressive load in strength exercise for the older adults who carried out the traditional weight training and inertial squat device training. The intensity of exercise on the inertial device was determined with the percentage of its maximum AM that had been previously specified with the baseline measurements of maximum ability of pull from a squat position (inertial repetition
maximum). Compared to the studies that have been carried out in this field so far (Norrbrand, 2008; Tesch et al., 2017) and with the intention of comparing exercise effects of inertial and traditional load, the velocity of the repetitions between exercise groups (Carroll et al., 2018) was standardized by executing fluent concentric squats during which the concentric and eccentric part of the exercise lasted one second.
Table 2. Resistance exercise protocol for older adult women with free weights and on the inertial squat device
Week |
%1RM1 |
Series |
Repetitions Rest period |
RPE |
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% inertial 1RM2 |
||||||
|
|
|
|
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1 IN |
40 |
3 |
|
|||
2 IN |
50 |
2 |
|
|||
3 |
60 |
2 |
|
|||
4 |
60 |
3 |
90'' |
|||
5 |
60 |
4 |
||||
|
||||||
6 |
70 |
2 |
|
|||
7 |
70 |
3 |
|
|||
8 |
70 |
4 |
|
Legend: IN – induction week, %1RM – repetition maximum, 1 – traditional group, 2 – inertial group, RPE – rate of perceived exertion
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EQOL Journal (2019) 11(1):
Measurements of inertial repetition maximum using the inertial squat device
Just as we indirectly carried out the measurements of the maximum load during a single repetition with kettlebell weights for all individuals to relatively adjust their exercise intensity (Brzycki, 1993), we also measured the maximum ability of the pull of the cylindrical weight from squat to rotation on the inertial device. Maximum angular velocity (ωmax) was measured with the use of
By adjusting all the cylindrical weights to an equal diameter and determine the execution of exercise repetition by slow
using the equation m=p*((2*Γmax- 2ω1*Jaxis)/(r^2*ω1)). In equation, the percentage of the maximum pull ability, also percentage of the maximum quantity of AM (% of inertial 1RM) in presented by 'p'; maximum quantity of AM measured at inertial 1RM is marked by 'Γmax'; the MMI of axis of rotation is defined by 'Jaxis'; radius of a cylindrical weights in standed by 'r' and the calculated angular velocity per second during slow
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Statistical Analysis
The descriptive analysis was performed using measures of central tendency (means±SD). The variables were tested for normality with the Shapiro- Wilk test (p>0.05; normality assumed). The baseline differences between the groups (control, traditional, inertial) were tested with a
We used a
Results
Prior to the exercise protocol there were no statistically significant differences in mean results of the functional reach test (F=0.781, p=0.466),
EQOL Journal (2019) 11(1):
Table 3. Test results pre and post the exercise intervention
|
|
Control |
|
|
Traditional |
|
|
Inertial |
|
|
|
(N=11) |
|
|
(N=14) |
|
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(N=12) |
|
|
|
|
|
|
|
|
|
|
|
Variable |
Initial |
Final |
ES |
Initial |
Final |
ES |
Initial |
Final |
ES |
Functional reach |
33±6.2 |
31.8±4.8 |
32.3±6 |
33.4±6.3 |
0.18 |
34.9±3.3 |
35.5±5.6 |
0.13 |
|
15.6±2.8 |
15.7±3.1 |
0.03 |
16.5±3.1 |
19.2±3.2 |
0.86 |
16.7±4.8 |
19.5±4.4* |
0.61 |
|
5.4±1.6 |
5.5±1.4 |
0.07 |
5.7 ±1.2 |
5.3 ±0.9 |
5.3±1.0 |
4.9±0.8 |
|||
565±125 |
617±151 |
0.38 |
581±93 |
672±120 |
0.85 |
593±134 |
653±121 |
0.47 |
Legend: Values are expressed as mean ± standard deviation. N – number of units, ES – effect size,
–significantly different from Control and initial, p<0.05
Significant time x group interaction (F=4.530, p=0.018) was only found in
According to the RPE results, no interaction (groups x intensity;
Discussion
The aim of the study was to examine practical implications and actual effects of a progressive resistance exercise protocol using a
vs. 50 vs. 60 vs. 70%). Pairwise comparisons – again corrected using a Bonferroni adjustment – reflect that results, regardless of the group, were all significantly different from each other (p>0.05) (Figure 2). Moreover, despite tendency of higher values in traditional groups, paired samples
Figure 2. Mean values and standard deviations of rate of perceived exertion (Borg's scale,
of leg extensor muscles, agility, balance, cardiovascular endurance and RPE - using Borg’s scale of perceived exertion.
The main finding of our study was that 8 weeks of inertial resistance exercise caused a significant 16% improvement in
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EQOL Journal (2019) 11(1):
walking, the ability to change direction during walking (timed
Although technique was attentively controlled, the results could be a consequence of the deviation in the repetition execution due to untrained individuals (Norrbrand et al., 2008). The timing of switching between the concentric and eccentric phases of contraction is crucial in executing repetitions correctly. The beginning of the active deceleration of the downward motion in the eccentric phase of squatting using the device also causes the development of higher force in the specific amplitude of a knee angle, with which the
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eccentric overload in submaximal repetition execution though has to be explored. Even though we did not entirely take full advantage of the potential of executing exercise repetitions using the developed inertial device, the exercise performed on it had similar or even more positive effects
Comparable studies have shown that inertial resistance exercise during which a higher MMI is used and subsequently lower velocities and higher force production are developed significantly affect hypertrophy and muscle strength, while a lower MMI with higher velocities and lower force production (fast repetitions and less force produced) significantly influences the development of muscle power (Naczk, Naczk,
The monitored values of RPE after each set of exercise were slightly lower at a certain exercise intensity in the inertial group compared to the traditional group. There was a significant difference at 70% intensity, so one could argue that inertial resistance exercise, which provides similar strength improvement over
resistance exercise. Structural viscoelastic mechanisms may make a greater contribution to force enhancement in the muscles of older adults compared to those of younger age. A relatively greater maintenance of eccentric strength shows that force production among elderly relies more on passive
EQOL Journal (2019) 11(1):
structural properties of muscles (Power, Herzog, & Rice, 2014). So lower values of RPE could be an effect of leaning on passive contractile elements in muscles during force production in eccentric contraction, which also causes less energy consumption and less exertion (Herzog, 2018). In this manner, with inertial load and the type of contractions used, we optimized the capability of producing muscle force among elderly.
In conclusion, the inertial squat device and the novel exercise intensity determination proved to be a practical and effective alternative to a traditional resistance exercise including squats, for older adult women. The applicability of the inertial exercise protocol enables an efficient alternative in resistance exercise among older adults. Moreover, in relationship to a traditional type of resistance exercise, it enables a comparable achievement of exercise objectives with less exertion. In general, resistance exercise improves health parameters; moreover, improvements in leg extensor muscle strength also positively influence elderly’s independence, balance and consequently prevents falls and fractures. By implementing
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How to cite this article:
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Spudić, D., Hadžić, V., Vodičar, J., Carruthers, J., & Pori, P. |
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(2019). Influence of inertial resistance squat exercise protocol |
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APA: |
based on novel exercise intensity determination on physical fitness |
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of older adult women. Exercise and Quality of Life, 11(1), |
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doi:10.31382/eqol.190604 |
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Spudić, Darjan, et al. "Influence of inertial resistance squat exercise |
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MLA: |
protocol based on novel exercise intensity determination on |
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physical fitness of older adult women." Exercise and Quality of |
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Life 11.1 (2019): |
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Spudić, Darjan, Vedran Hadžić, Janez Vodičar, Jamie Carruthers, |
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and Primož Pori. "Influence of inertial resistance squat exercise |
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Chicago: |
protocol based on novel exercise intensity determination on |
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physical fitness of older adult women." Exercise and Quality of |
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Life 11, no. 1 (2019): |
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