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3 Different Types of Strength Training in Older Women Article  in  International Journal of Sports Medicine · July 2012 DOI: 10.1055/s-0032-1312648 · Source: PubMed

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962 Training & Testing

Authors

C. S. Correa1, D. P. LaRoche2, E. L. Cadore1, A. Reischak-Oliveira1, M. Bottaro3, L. F. M. Kruel1, M. P. Tartaruga4, R. Radaelli1, E. N. Wilhelm1, F. C. Lacerda1, A. R. Gaya1, R. S. Pinto1

Affiliations

Affiliation addresses are listed at the end of the article

Key words ▶ rapid strength training ● ▶ elderly women ● ▶ functional capacity ● ▶ reaction time ● ▶ muscle thickness ●

Abstract

accepted after revision April 17, 2012 Bibliography DOI http://dx.doi.org/ 10.1055/s-0032-1312648 Published online: July 10, 2012 Int J Sports Med 2012; 33: 962–969 © Georg Thieme Verlag KG Stuttgart · New York ISSN 0172-4622 Correspondence Prof. Cleiton Silva Correa Exercice Research Laboratory – Physical Education School – UFRGS Federal University of Rio Grande do Sul, RS, Brazil 750 Felizardo Furtado Street – Jardim Botânico – CEP 90690200 Porto Alegre – RS – Brazil 90690-200 porto alegre Brazil Tel:.+55/51/9358 9414 Fax: +55/51/3308 5842 [email protected]

▼

The objective of the present study was to evaluate and compare the neuromuscular, morphological and functional adaptations of older women subjected to 3 different types of strength training. 58, healthy women (67 ± 5 year) were randomized to experimental (EG, n = 41) and control groups (CG, n = 17) during the first 6 weeks when the EG group performed traditional resistance exercise for the lower extremity. Afterwards, EG was divided into three specific strength training groups; a traditional group (TG, n = 14), a power group (PG, n = 13) that performed the concentric phase of contraction at high speed and a rapid strength group (RG, n = 14) that performed a lateral box jump exercise emphasizing the stretchshortening-cycle (SSC). Subjects trained 2 days per week through the entire 12 weeks. Following 6 weeks of generalized strength training, significant improvements occurred in EG for knee extension one-repetition (1RM) maximum strength (+19 %), knee extensor muscle thickness (MT, +15 %), maximal muscle activation (+44 % average) and onset latency ( − 31 % average) for

Introduction

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Biological aging is associated with a decline in neuromuscular function and morphology, resulting in a decrease in maximal strength, power [1, 24, 25] and neuromuscular reaction time [39, 40]. The factors include changes in neural recruitment pattern of motor units, and declines in maximal firing rate and synchronization of motor units [19, 43]. The morphological changes are associated mainly with muscle fiber atrophy, with consequent decreases in cross-sectional area and muscle thickness (MT), especially in type II fibers, which have the greatest motor unit strength, power and speed of contraction. These

Correa CS et al. Three Different Types of … Int J Sports Med 2012; 33: 962–969

vastus lateralis (VL), vastus medialis (VM) and rectus femoris (RF) compared to CG (p < 0.05). Following 6 more weeks of specific strength training, the 1RM increased significantly and similarly between groups (average of +21 %), as did muscle thickness of the VL (+25 %), and activation of VL (+44 %) and VM (+26 %). The onset latency of RF (TG = 285 ± 109 ms, PG = 252 ± 76 ms, RG = 203 ± 43 ms), reaction time (TG = 366 ± 99 ms, PG = 274 ± 76 ms, RG = 201 ± 41 ms), 30-s chair stand (TG = 18 ± 3, PG = 18 ± 1, RG = 21 ± 2) and counter movement jump (TG = 8 ± 2 cm, PG = 10 ± 3 cm, RG = 13 ± 2 cm) was significantly improved only in RG (p < 0.05). At the end of training, the rate of force development (RFD) over 150 ms (TG = 2.3 ± 9.8 N·s − 1, PG = 3.3 ± 3.2 N·s − 1, RG = 3.8 ± 6.8 N·s − 1, CG = 2.3 ± 7.0 N·s − 1) was significantly greater in RG and PG than in TG and CG (p < 0.05). In conclusion, rapid strength training is more effective for the development of rapid force production of muscle than other specific types of strength training and by consequence, better develops the functional capabilities of older women.

changes negatively affect the muscles of the lower limbs, particularly at the knee and ankle [6, 20], leading to impaired mobility and ability to perform activities of daily living (ADL). For example, Skelton et al. showed that aging decreases strength and power capacities and these variables are related to the ability to perform functional activities like standing and stepping up [48]. The impact of aging on the neuromuscular system differs not only in terms of muscle groups and type of contraction studied [21, 29, 50], but also in the onset latency of muscle activation (OM) [37]. From a functional and therapeutic perspective, the capacity for the rapid applica-

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3 Different Types of Strength Training in Older Women

Training & Testing 963

Methods

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Subjects The volunteer sample was comprised of 58 older women, age 67 ± 5 years, with a mean height of 158.1 ± 10.2 cm and 38.0 ± 5.3 % body fat, who had not engaged in regular and systematic ST for at least 1 year before the study. The study excluded individuals with a history of severe endocrine, metabolic and neuromuscular diseases. Subjects were recruited through advertisement in a widely read local newspaper. Prior to participation, subjects were carefully informed of the design of the study, especially the possible risks and discomforts related to the procedures. Subjects then gave their written, informed consent. The study was performed according to the ethical standards of the IJSM [27] and the protocol was approved for the use of human subjects by the University’s Institutional Ethics and Research Committee (Protocol No. 19322).

Body composition Body mass and height were measured using an ASIMED (MG, Brazil) analog scale (resolution of 0.1 kg) and a stadiometer (resolution of 1 mm), respectively. Body composition was assessed using the skinfold technique. The same technician obtained all anthropometric measurements on the right side of the subject’s body. Skinfold thickness was obtained with a Cescorf skinfold calliper. A 7-site skinfold equation was used to estimate body density [13, 31] and body fat was subsequently calculated using the Siri equation [14].

Experimental design The experiment was divided into 2 phases. In the first phase, consisting of 6 weeks, the subjects were randomly divided into an experimental group (EG, n = 41) that performed traditional resistance exercise and a non-exercising control group (CG, n = 17). The randomization resulted in no significant difference ▶ Table 1) between groups for any of the performance variables (● prior to training. The EG performed leg press, knee extension, and knee flexion exercises, twice a week for six weeks, with linear, progressive increases in intensity and volume, accrued [5, 35] over two meso-cycles. During weeks one to three the EG performed two sets of each exercise with a maximum of 15–20 repetitions (RM), and during weeks 4–6, performed three sets of 12–15 RM with a time interval between sets and exercises of 120 s. In the second phase of the study also lasting 6 weeks, the EG was further divided into 3 subgroups that carried out traditional strength training (TG, n = 14), power training (PG, n = 13), and ▶ Fig. 1). This phase had a rapid strength training (RG, n = 14) (● similar periodization scheme that used 3 sets of 10–12 RM during weeks 7–9 and 4 sets of 8–10 RM during weeks 10–12. TG and PG performed the same exercises for the lower limbs as was done in the first 6 weeks (leg press, knee extension and knee flexion). However, in the second phase while TG performed these exercises in a controlled fashion (e. g. 2 s concentric, 2 s eccentric), PG performed the exercises with maximal speed during the concentric phase but maintained a 2 s pace during the eccentric movement. In RG the leg press exercise was replaced ▶ Fig. 2) that relied heavily on by a lateral box jump exercise (● the SSC (i. e., a plyometric exercise) characterized by a high▶ Fig. 2c) followed immediately intensity eccentric component (● ▶ Fig. 2b) by a rapid and powerful concentric contraction (● [32, 33, 42]. The exercise consisted of rapidly, and explosively, jumping up, over the box, and down with the alternate leg on a box with a pre-defined height of either 10, 20 or 30 cm (increased 10 cm every 2 weeks). 3 sets of the lateral box jump exercise were performed during weeks 7–9 and 4 sets during weeks 10–12. This body-weight resisted exercise required dynamic knee and hip extension with the goal of performing the maximum number of side-to-side repetitions in the allotted time (15–20 s). The CG did not perform any resistance exercise during the 12 weeks of the intervention.

Maximal dynamic strength Maximal strength was assessed using the one-repetition maximum knee extension test (1RM) in a knee extension machine (World Sculptor-RS, Brazil). 1 week prior to the test day, subjects were familiarized with all procedures. On the test day, the subjects warmed up for 5 min on a cycle ergometer, stretched all major muscle groups, and performed the specific movements of the exercise test. Each subject’s maximal load was determined Correa CS et al. Three Different Types of … Int J Sports Med 2012; 33: 962–969

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tion of strength (including reaction time) has an impact on the ability to recover from a loss of balance as Tang et al. [49] and Thelen et al. [50] have demonstrated. In turn, the ability to rapidly produce force is vital and can serve as a preventive mechanism in falls [51]. Injuries as a result of falls and their associated complications (hospitalization, surgery to implant prostheses, etc…) result in high costs and represent a serious public health problem [51]. Moreover, falls in the elderly often result in death. The incidence of falls in older women is higher than in older men, due to their low level of physical activity [46] and can threaten the independent lifestyle of these individuals. The adoption of a regular and systematic program of strength training (ST) reduces the speed at which the muscle fibers deteriorate, increases absolute and relative strength, improves balance and increases muscle power helping the elderly reduce fall risk as well as maintain ADL and independence [18, 52]. In this context, participation in traditional strength training, power training, or rapid strength training that uses the stretch-shortening-cycle (SSC) should aid in the development of maximal strength, power and rapid muscle contractions, respectively, which are essential for the maintenance of motor health and quality of life in older adults. Among the 3 types of strength training above, power training has been shown to be more suitable for the improvement of functional abilities in older men that traditional strength training [28, 45]. Since rapid strength training, or plyometric training, is purported to improve numerous aspects of muscle performance (i. e., maximal strength, power and reaction time), from a neuromuscular point of view it may be the most appropriate training modality to increase muscle responsiveness for older women. However, to the authors’ knowledge there are no published studies that have evaluated and compared the effects of three different types of strength training on neuromuscular and morphological parameters as well as the functional capabilities of older women. Therefore, the purpose of this study was to evaluate and compare the neuromuscular and morphological adaptations, and functional abilities of older women subjected to 3 different types of strength training. Our hypothesis was that rapid strength training would be more effective than traditional strength training for the improvement of reaction and muscle activation times resulting in greater improvement in functional performance.

964 Training & Testing

Variables

EG, n = 42 Pre

1 RM-KE (kg) MT-VL (mm) MT-VM (mm) MT-RF (mm) EMG-VL (μV) EMG-VM (μV) EMG-RF (μV) OM-VL (ms) OM-VM (ms) OM-RF (ms) RT (ms) RFD-0–0.15 s (N·s − 1) RFD-0–0.25 s (N·s − 1) STS (n ° repetition) CMJ (cm)

CG, n = 17

Week 6

42.5 ± 8.1 16.1 ± 2.3 14.0 ± 3.3 16.2 ± 2.9 108.2 ± 51.5 78.2 ± 33.7 66.7 ± 43.3 324.5 ± 69.4 356.8 ± 68.7 346.2 ± 66.3 473.2 ± 67.1 2.3 ± 7.3 1.6 ± 4.1 14.1 ± 1.5 7.4 ± 2.5

Pre

50.4 ± 8.4†* 17.9 ± 2.1†* 16.7 ± 2.2†* 18.7 ± 2.1†* 146.3 ± 33.2†* 117.8 ± 27.9†* 99.7 ± 23.3†* 194.3 ± 51.6†* 236.9 ± 54.4†* 275.9 ± 49.9†* 318.3 ± 50.1†* 2.6 ± 7.9 1.8 ± 4.8 17.2 ± 1.3†* 8.2 ± 2.1

Week 6

39.1 ± 8.3 16.7 ± 2.9 14.4 ± 3.6 16.8 ± 2.1 119.9 ± 44.9 88.7 ± 34.5 77.2 ± 29.8 343.8 ± 76.3 298.7 ± 67.9 350.7 ± 64.9 457.4 ± 91.5 2.7 ± 7.0 1.7 ± 7.5 15.7 ± 2.0 7.6 ± 2.5

36.8 ± 9.0 16.1 ± 3.1 14.9 ± 3.4 16.0 ± 2.0 106.4 ± 34.6 79.8 ± 33.5 71.3 ± 27.1 311.2 ± 75.7 320.9 ± 63.8 328.8 ± 63.7 398.6 ± 80.5 2.4 ± 8.7 1.8 ± 6.7 15.7 ± 2.0 7.9 ± 2.5

Table 1 Comparison of muscle performance between those conducting generalized strength training and controls, before and after 6 weeks of strength training.

Values are mean ± SD † Significant difference between pre and week 6 (p < 0.05) * Significant difference between Experimental Group (EG) and control group (CG) (p < 0.05) 1RM = One Repetition Maximum, KE = knee extension, MT = muscle thickness, VL = vastus lateralis, VM = vastus RT = Reaction Time, RFD = Rate of Force Development, STS = 30-s Sit-to-Stand, CMJ = Counter-Movement Jump

Fig. 1 Simplified study experimental design. EG = Experimental Group, TG = Traditional Training Group, PG = Power Training Group and RG = Rapid Training Group.

Division of Training Groups

6 weeks

Pre

TG

EG (generalized period) PG

12 weeks (Specifics Strength Training)

RG

ronome (Quartz, CA, USA). The test-retest reliability coefficient (ICC) was 0.99 for KE 1RM.

Muscle thickness

Fig. 2 Lateral box jump used by the Rapid Training Group demonstrating the a starting position, b box jump, and c landing on the alternate leg which was then instantly repeated in the opposite direction ( in the order c – b – a).

with no more than 5 attempts with a 4-min recovery between attempts. Performance time for each contraction (concentric and eccentric) was 2 s and was controlled by an electronic met-

Correa CS et al. Three Different Types of … Int J Sports Med 2012; 33: 962–969

The evaluation of muscle thickness (MT) was performed using images obtained with an ultrasound device (Philips, VMI, Industries e Commercial Ltda. Lagoa Santa, MG, Brazil) in B-mode. During the evaluation of MT, subjects remained in a supine position with the assessed leg extended and relaxed for 10 min to restore the normal flow of body fluids. A transducer with a sampling frequency of 7.5 MHz was positioned perpendicularly to the muscles. For image acquisition, we used a water-based gel that promotes acoustic contact without causing pressure with the transducer over the skin. The subcutaneous adipose tissue and bone tissue were identified by the ultrasound image, and the distance between them was defined as the MT. The evaluation of MT was made in the dominant segment, and the same evaluator performed all measurements. The evaluation of MT in the knee extensors was performed at the following points: the vastus lateralis (VL); the midpoint between the greater trochanter and lateral epicondyle of the femur; the vastus medialis (VM), measured at 30 % of the distance from the lateral epicondyle of the femur to the greater trochanter; rectus femoris (RF), measured at two-thirds of the distance from the greater trochanter of the femur to the lateral epicondyle and 3 cm lateral from the midline of the limb [34].

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medialis, RF = rectus femoris, EMG = electromyography for maximal muscle activation, OM = Muscle Onset Latency,

Training & Testing 965

Muscle activation was determined by recording the surface electromyogram (EMG) during a maximal isometric leg press. First, the electrode sites were prepared by shaving the area and cleaning the skin by abrasion with cotton moistened with alcohol gel as reported by Hakkinen et al. [22]. The electrodes were placed in a bipolar configuration, along the direction of the muscle fibers over the muscle belly of VL, VM and RF of the right leg. The distance between electrodes was fixed at 2.2 cm (MIOTEC model HALL), and for each collection, the level of resistance between the electrodes was measured by a multimeter to be below 3 000 Ohms. A reference electrode was placed on the tibial tuberosity of the right leg. The subjects were positioned in the leg press with a load cell attached to the equipment to measure force which was recorded synchronously with the EMG signal of VL, VM and RF muscles. The load cell and EMG signal conductor cables were connected to a 4 channel, analog to digital (A/ D) board (Miotool 400) and the data were sampled at 2 000 Hz using a personal computer and acquisition software (MIOTEC, Biomedical Equipment, Porto Alegre- Brazil). The EMG signal was digitally conditioned using a fifth-order, band-pass Butterworth filter, with cutoff frequencies of 20 and 500 Hz and the force data were filtered using a Butterworth filter with cutoff frequencies of 0–9 Hz [3, 12]. Participants performed 3, maximal, voluntary, isometric contractions (MVIC), for 5 s in response to a light stimulus during which they were verbally encouraged to produce a maximal effort. The angles of the hip, knee and ankle were positioned and maintained at approximately 90 ° and 3–5 min of recovery was provided between attempts. The raw EMG signal obtained during contraction was quantified as the root mean square (RMS). Maximal activation of muscle was taken as the highest RMS EMG observed during the plateau of the force curve. The determination of onset latency of the VL, VM and RF, as well as reaction time and the rate of force production (RFD) are described below. Consistent positioning of EMG electrodes at the different test times was controlled by means of marks made on the skin of each individual with a pen and the mapping technique proposed by Narici et al. [44]. All data were analyzed using Matlab software (version 5.3).

ferent time intervals (0–0.15 s and 0–0.25 s) similar to the methods of Aagaard et al. [2].

30 s sit-to-stand The 30 s sit-to-stand test began with the participant seated in the center of a chair (height 43 cm) with the back straight and feet on a flat surface positioned about shoulder-width apart, arms crossed at chest height, with an angle of approximately 90 ° for hip and knee flexion. At a verbal signal, the participant rose to a full upright position and then returned to the initial seated position. The participant was encouraged to complete as many repetitions as possible within a 30-s period [28, 48].

Counter movement jump (CMJ) To carry out the CMJ, subjects were positioned on a force platform (Advanced Mechanical Technology, Inc. Watertown, MA, USA, Model OR6-WP-1000) and were familiarized to the procedure by performing several jumps. They were instructed to jump with their hands on their waist while avoiding the bending of their legs during flight and trying to achieve the maximal possible time in the air. After the familiarization, the subjects performed 3 CMJ on the force platform with 2 min rest intervals. There was no restriction on the angle of knee flexion during the eccentric phase of the CMJ [15, 30, 33]. The greatest jump height was used for analysis and was determined by the equation provided by Bosco et al. [10]: [(height = 9.8·(Flight time)2/6)], using Matlab software.

Statistical analysis Descriptive statistics were calculated and are presented as mean ± SD. Normality of the data was assessed using the Kolmogorov-Smirnov test and Levene’s homogeneity of variance test. For comparisons between groups prior to training, and following 6 and 12 weeks of strength training, a 2-way repeated measures analysis of variance (ANOVA) was used (2 groups × 3 times), with Bonferroni post-hoc tests. In addition, a one-way ANOVA was performed to compare the relative changes (Δ %) between the experimental and control groups at different times in the study (after 6 and 12 weeks of training). The significance level for all statistical tests was p < 0.05 and all analyses were performed using SPSS statistical software version 17.0.

Reaction time and muscle onset latency The force vs. time and EMG vs. time curves were used to determine reaction time and the onset latency of VL, VM and RF muscles, respectively. The reaction time and muscle onset latency were recorded in milliseconds (ms) and analyzed by an algorithm developed in Matlab (version 5.3). The reaction time was defined as the time between the light stimulus to the point where the force curve increased more than 3 standard deviations (SD) above the baseline reference period (25 ms period prior to force development). The onset latency of VL, VM and RF muscles was defined as the time between the light stimulus to the point where the RMS EMG signal rose more than 3 SD above the mean baseline electrical activity of the muscles (200 ms period prior to the MVIC) for a minimum of 25 ms [9].

Rate of force development (RFD) The RFD was measured from the force vs. time curve that was obtained during the maximal isometric leg press and was calculated as the change in force divided by the change in time (slope of the force vs. time curve). The RFD (N·s − 1) was calculated in Matlab from the MVIC that elicited the highest force [4] at 2 dif-

Results

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During the initial 6 weeks of strength training, when there was no division between different types of training, a significant increase occurred in EG for maximal dynamic strength (1RM), maximal activation of the quadriceps muscles (VL, VM and RF), muscle thickness (VL, VM, and RF) and the number of chair ▶ Table 1). During the same period, stand repetitions (p < 0.05, ● significant decreases occurred for muscle onset latency (VL, VM and RF) and reaction time (p < 0.05). There were no significant changes for these variables for CG. This resulted in significant differences between EG and CG at 6 weeks for maximal strength, muscle thickness, muscle activation, muscle onset latency, reaction time and sit-to-stand performance (p < 0.05). Following the initial 6-week period there were no changes in RFD or CMJ height for either group. After the division of the general strength training group (EG) into specific training groups (TG, PG and RG, from 6–12 weeks), ▶ Fig. 3a), muscle significant increases in knee extension 1RM (● Correa CS et al. Three Different Types of … Int J Sports Med 2012; 33: 962–969

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Muscle activation

966 Training & Testing

a 100

b

* 30

Δ 22%

Δ 20% Δ 17% Maximum Repetitions (n°)

1RM Knee Extension (kg)

Δ 21% 80

60

40

20

0

Δ 8%

TG

PG

20

10

0 TG

c

Δ 7%

PG

RG

RG

d

800

25

*

20 Δ 25% Δ 9%

400

Δ –29%

200

Jump Height (cm)

time (ms)

Δ 15%

Δ 8%

15 Δ 4% 10

5

0

0 TG

PG

RG

TG post 6

PG

RG

post 12

Fig. 3 Percent change (Δ %) in a One-repetition maximum (1RM) knee extension strength, b 30-s sit-to-stand repetitions, c Reaction time and d Countermovement-jump height between weeks 6 and 12 of specific strength training. Values are mean ± SD. † Significant difference between week 6 and week 12 of specific strength training (p < 0.05). * Significant difference between RG (Rapid Strength Training Group) in relation to groups TG (Traditional Strength Training Group) and PG (Power Training Group) (p < 0.05).

thickness of VL, muscle activation of the VM and VL muscles ▶ Table 2, p < 0.05) with occurred in each of the training groups (● no differences between groups. Over the same period there were no changes in any of the measures for CG. Reaction time ▶ Fig. 3c) and muscle onset latency were significantly reduced (● in RG but not in the other training groups. Likewise, the per▶ Fig. 3b) and CMJ (● ▶ Fig. 3d) formance in 30-s Sit-to-Stand (● was significantly higher in RG compared to TG and PG groups. The RFD in the period from 0–0.15 s of contraction was significantly higher in RG and PG groups following training (p < 0.05), ▶ Table 2). but not in TG (●

Discussion

▼

The major findings of this study were that rapid strength training was more effective than traditional strength training and power training for 30-s Sit-to-Stand and counter movement jump performance tests as well as for the activation of the VL Correa CS et al. Three Different Types of … Int J Sports Med 2012; 33: 962–969

and VM. In addition, 3 specific types of strength training (TG, PG and RG) resulted in equal increases in maximal dynamic knee extension strength and quadriceps muscle thickness. In relation to the development of maximal strength, our results agree with previous studies that observed improvement in strength related to increases in muscle activation and muscle hypertrophy [7, 17, 18, 26]. In the present study there was an increase in muscle activation of VM and VL muscles suggesting an increased recruitment and firing frequency of motor units, with no significant difference between training type [23, 24]. Morphological adaptations were evident as there was an increase in muscle thickness of VL in all strength training groups indicating that hypertrophy likely contributed to the increased maximal, dynamic strength [6, 13, 28]. However, the resistance training program used in this study was short (12 weeks) and the differences in neuromuscular adaptation demonstrated between training groups in this study should be investigated over longer periods (e. g. 1 year). Nonetheless, these results are important because they show that the RG group that replaced a

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* 600

Training & Testing 967

Table 2 Comparison of muscle performance between those conducting generalized strength training, power training, reactive strength training and controls, before and after six weeks of specific strength training. Variables MT-VL (mm) MT-VM (mm) MT-RF (mm) EMG-VL (μV) EMG-VM (μV) EMG-RF (μV) OM-VL (ms) OM-VM (ms) OM-RF (ms) RFD-0–0.15 s (N·s − 1) RFD-0–0.25 s (N·s − 1)

TG, n = 14

PG, n = 13

RG, n = 14

Week 6

Week 12

Week 6

Week 12

Week 6

17.8 ± 1.6 15.2 ± 3.1 18.2 ± 2.9 136.3 ± 32.2 117.1 ± 29.4 99.3 ± 37.1 194.3 ± 51.6 205.1 ± 54.3 255.9 ± 49.9 2.6 ± 0.8 1.8 ± 0.6

21.8 ± 2.9† 16.1 ± 2.3 19.8 ± 3.6 182.0 ± 39.4† 144.8 ± 14.6† 119.6 ± 30.7 272.6 ± 98.2 254.9 ± 94.6 285.9 ± 109.0 2.3 ± 0.9 1.7 ± 0.4

18.0 ± 2.3 15.6 ± 2.6 18.1 ± 3.2 139.3 ± 55.2 120.9 ± 19.3 89.6 ± 39.9 195.7 ± 42.3 218.9 ± 38.7 223.7 ± 51.4 2.3 ± 0.3 1.8 ± 0.3

23.2 ± 3.9† 16.9 ± 3.6 19.9 ± 3.1 195.9 ± 37.8† 143.7 ± 18.9† 118.7 ± 27.6 229.2 ± 75.7 239.1 ± 96.7 252.8 ± 63.7 3.3 ± 0.3†£ 2.3 ± 0.7

17.8 ± 3.1 14.7 ± 2.6 18.0 ± 3.2 158.9 ± 76.3 126.4 ± 35.4 108.4 ± 28.6 262.5 ± 56.1 226.6 ± 38.9 291.2 ± 44.3 2.5 ± 0.7 1.7 ± 0.6

CG, n = 17

Week 12 21.8 ± 2.3† 16.9 ± 2.9 19.8 ± 4.4 245.5 ± 55.7† 169.7 ± 34.7† 117.7 ± 24.9 229.2 ± 93.4 248.6 ± 59.3 203.0 ± 43.6†* 3.8 ± 0.6†£ 2.4 ± 0.7

Week 6

Week 12

16.1 ± 3.1 14.9 ± 3.4 16.0 ± 2.0 106.4 ± 34.6 79.8 ± 33.5 71.3 ± 27.1 311.2 ± 75.7 320.9 ± 63.8 328.8 ± 63.7 2.4 ± 0.8 1.8 ± 0.6

16.2 ± 2.1 15.1 ± 4.6 16.8 ± 3.7 98.1 ± 34.3 86.8 ± 34.8 74.3 ± 28.2 289.3 ± 58.1 298.4 ± 59.1 292.1 ± 44.9 2.3 ± 0.7 1.8 ± 0.6

Values are mean ± SD † Significant difference between week 6 and week 12 of specific strength training (p < 0.05) *Significant difference between RG = Reactive Strength Training in relation to TG = Traditional Strength Training and PG = Power Training (p < 0.05) £Significant difference between RG = Reactive Strength Training and PG = Power Training in relation to TG = Traditional Strength Training (p < 0.05) CG = Control Group, MT = muscle thickness, VL = vastus lateralis, VM = vastus medialis, RF = rectus femoris, EMG = electromyography for maximal muscle activation, OM = Muscle

traditional overload strength exercise (i. e., leg press) with one that used the SSC at a high execution speed (i. e., lateral box jump) did not have an impaired ability to increase maximal strength and muscle thickness. This can be partially explained by the fact that the use of exercises with SSC promote the recruitment of motor units with high thresholds of activation [32, 41], which may have contributed to the increase in maximal activation in this group. Also, similar changes in muscle area have been shown in response to training that uses SSC and traditional strength training in young, untrained individuals when the volume of exercise was controlled between the types of training [15]. In addition to maximal muscle activation, muscle onset latency and reaction time are critical to the evaluation of the neuromuscular responsiveness of older adults [49]. In the present study, we observed a significant reduction in muscle onset latency for the RF muscle in RG, demonstrating faster muscle activation in the group that performed the rapid strength exercise. In addition, RG showed a faster reaction time, which represents a practically significant improvement in neuromuscular responsiveness in older women. Our results agree with previous literature, which demonstrated that the use of strength exercises in which SSC is present, as in the lateral box jump exercise used in this study, improves the speed of activation and reaction time of biarticular muscles such as RF [16]. Functionally, the faster muscle onset and reaction time should increase the ability of older women to avoid obstacles and reduce the frequency of falls [36, 45]. In fact, LaRoche et al. [38] showed that older women with a lower propensity for falls had faster motor times of the ankle and knee muscles. The absence of change in muscle onset latency of the mono-articular muscles VL and VM may possibly be due to changes in muscle recruitment strategy during the evaluation task [43]. It has been shown that neuromuscular adaptations to training may not occur in all muscle groups assessed [48]. In this study, 6 weeks of rapid strength training was effective at further reducing neuromuscular reaction time which did not ▶ Fig. 3c). occur with traditional strength or power training (● This result demonstrates that RG, in addition to increasing the maximal dynamic force to the same extent as PG and TG,

improved the ability to quickly activate the knee extensors. Our results corroborate the findings of Caserotti et al. [15], who showed increases in the rate of force application in the knee extensors of older adults, after 12 weeks of explosive, high resistance strength training, in just 2 sessions per week with a load of 70–80 % 1RM. As in the present study, these authors demonstrated that a training rate of only 2 times a week can improve the power of older women. The rate of force development is one variable that represents the ability to quickly generate force and has high a correlation with functional capacity in the elderly [11, 47]. In this study, the RFD in 0.15 s was significantly increased in RG and PG, whereas TG showed no change in RFD after training. This is likely due to specificity of training as the speed of muscle contraction was higher in these types of training. These results emphasize the importance of performing exercises with maximal or near maximal speed since the performance of exercises with greater speed seems to be more effective for the development of rapid muscle strength [8, 11]. Improving RFD may have additional functional benefits as it has been shown to be positively related to neuromuscular economy during aerobic exercise, as well as aerobic power in elderly [14]. The rapid development of force, along with the concomitant increase in maximal strength and muscle mass is of great importance for functional capacity in older women. The results of this study suggest that rapid strength training appears to be the best strategy for development of these capabilities with the added benefit of faster neuromuscular reaction times. In parallel with the neuromuscular parameters, rapid strength training was shown to be most effective for increasing the performance of functional tests, as demonstrated by the increase in the number of repetitions in the 30-s Sit-to-Stand and height of the CMJ. With respect to performance during CMJ, our results are consistent with other studies showing that traditional strength training results in little or no improvement in the performance of jumps [15, 30]. This implies the need for developing strategies that use exercises that rely on the SSC (e. g. jumping) [33] as well as on the rapid production of force of the lower limbs as these are key factors contributing to the maintenance of ADL in older adults [15, 18, 48]. It should be noted that the rapid strength training Correa CS et al. Three Different Types of … Int J Sports Med 2012; 33: 962–969

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Onset Latency, RFD = Rate of Force Development

program employed in this study was preceded by a general strength training which may have prepared the nervous, muscular, ligamentous and skeletal systems of individuals in RG to tolerate the SSC exercises. However, our results emphasize that short periods of rapid strength training seem to be sufficient to improve lower-extremity functional performance.

Conclusion

▼

Rapid strength training enhances neuromuscular parameters related to muscle force production, it decreases the time of muscle activation, and improves the functional capacity of elderly women in greater magnitude than traditional strength and power training. Moreover, substituting a rapid strength exercise for a traditional high-load exercise does not prevent the development of maximal dynamic strength, muscle thickness, or activation of the quadriceps muscles as these adaptations were similar between the specific types of strength training.

Acknowledgements

▼

The authors would like to thank the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES-Brazil) and the Conselho de Desenvolvimento Tecnológico e Científico (CNPq-Brazil) for financial support. We would also like to thank our colleagues Kelly Costa, Bruna Gonçalvez and Fernanda Weber for technical assistance during data collection. Affiliations Physical Education Scholl, Federal University of Rio Grande do Sul, Porto Alegre, Brazil 2 Department of Kinesiology, University of New Hampshire, Durham, United States 3 College of Physical Education, University of Brasília, Brasília, Brazil 4 MidWest State University, UNICENTRO, Department of Physical Education DEDUF/G Laboratory of Biomechanics and Ergonomics 1

References 1 American College of Sports Medicine position stand. Progression models in resistance training for healthy adults. Med Sci Sports Exerc 2009; 41: 687–708 2 Aagaard P, Simonsen EB, Andersen JL, Magnusson P, Dyhre-Poulsen P. Increased rate of force development and neural drive of human skeletal muscle following resistance training. J Appl Physiol 2002; 93: 1318–1326 3 Alberton CL, Cadore EL, Pinto SS, Tartaruga MP, da Silva EM, Kruel LF. Cardiorespiratory, neuromuscular and kinematic responses to stationary running performed in water and on dry land. Eur J Appl Physiol 2011; 111: 1157–1166 4 Andersen JL, Aagaard P. Effects of strength training on muscle fiber types and size; consequences for athletes training for high-intensity sport. Scand J Med Sci Sports 2010; 20: (Suppl 2): 32–38 5 Baker DG, Newton RU. Adaptations in upper-body maximal strength and power output resulting from long-term resistance training in experienced strength-power athletes. J Strength Cond Res 2006; 20: 541–546 6 Bean JF, Herman S, Kiely DK, Frey IC, Leveille SG, Fielding RA, Frontera WR. Increased Velocity Exercise Specific to Task (InVEST) training: a pilot study exploring effects on leg power, balance, and mobility in community-dwelling older women. J Am Geriatr Soc 2004; 52: 799–804 7 Bean JF, Kiely DK, Herman S, Leveille SG, Mizer K, Frontera WR, Fielding RA. The relationship between leg power and physical performance in mobility-limited older people. J Am Geriatr Soc 2002; 50: 461–467 8 Behm DG, Sale DG. Velocity specificity of resistance training. Sports Med 1993; 15: 374–388

Correa CS et al. Three Different Types of … Int J Sports Med 2012; 33: 962–969

9 Bennell K, Duncan M, Cowan S, McConnell J, Hodges P, Crossley K. Effects of vastus medialis oblique retraining versus general quadriceps strengthening on vasti onset. Med Sci Sports Exerc 2010; 42: 856–864 10 Bosco C, Luhtanen P, Komi PV. A simple method for measurement of mechanical power in jumping. Eur J Appl Physiol 1983; 50: 273–282 11 Bottaro M, Machado SN, Nogueira W, Scales R, Veloso J. Effect of high versus low-velocity resistance training on muscular fitness and functional performance in older men. Eur J Appl Physiol 2007; 99: 257–264 12 Cadore EL, Pinto RS, Alberton CL, Pinto SS, Lhullier FL, Tartaruga MP, Correa CS, Almeida AP, Silva EM, Laitano O, Kruel LF. Neuromuscular economy, strength, and endurance in healthy elderly men. J Strength Cond Res 2011; 25: 997–1003 13 Cadore EL, Pinto RS, Lhullier FL, Correa CS, Alberton CL, Pinto SS, Almeida AP, Tartaruga MP, Silva EM, Kruel LF. Physiological effects of concurrent training in elderly men. Int J Sports Med 2010; 31: 689–697 14 Cadore EL, Pinto RS, Pinto SS, Alberton CL, Correa CS, Tartaruga MP, Silva EM, Almeida AP, Trindade GT, Kruel LF. Effects of strength, endurance, and concurrent training on aerobic power and dynamic neuromuscular economy in elderly men. J Strength Cond Res 2011; 25: 758–766 15 Caserotti P, Aagaard P, Larsen JB, Puggaard L. Explosive heavy-resistance training in old and very old adults: changes in rapid muscle force, strength and power. Scand J Med Sci Sports 2008; 18: 773–782 16 Da Silva EM, Brentano MA, Cadore EL, De Almeida AP, Kruel LF. Analysis of muscle activation during different leg press exercises at submaximum effort levels. J Strength Cond Res 2008; 22: 1059–1065 17 Fiatarone MA, Marks EC, Ryan ND, Meredith CN, Lipsitz LA, Evans WJ. High-intensity strength training in nonagenarians. Effects on skeletal muscle. JAMA 1990; 263: 3029–3034 18 Fielding RA, LeBrasseur NK, Cuoco A, Bean J, Mizer K, Fiatarone Singh MA. High-velocity resistance training increases skeletal muscle peak power in older women. J Am Geriatr Soc 2002; 50: 655–662 19 Frontera WR, Hughes VA, Krivickas LS, Kim SK, Foldvari M, Roubenoff R. Strength training in older women: early and late changes in whole muscle and single cells. Muscle Nerve 2003; 28: 601–608 20 Frontera WR, Hughes VA, Lutz KJ, Evans WJ. A cross-sectional study of muscle strength and mass in 45- to 78-yr-old men and women. J Appl Physiol 1991; 71: 644–650 21 Granacher U, Gruber M, Gollhofer A. Resistance training and neuromuscular performance in seniors. Int J Sports Med 2009; 30: 652–657 22 Hakkinen K, Alen M, Kallinen M, Newton RU, Kraemer WJ. Neuromuscular adaptation during prolonged strength training, detraining and re-strength-training in middle-aged and elderly people. Eur J Appl Physiol 2000; 83: 51–62 23 Hakkinen K, Kallinen M, Izquierdo M, Jokelainen K, Lassila H, Malkia E, Kraemer WJ, Newton RU, Alen M. Changes in agonist-antagonist EMG, muscle CSA, and force during strength training in middle-aged and older people. J Appl Physiol 1998; 84: 1341–1349 24 Hakkinen K, Kraemer WJ, Newton RU, Alen M. Changes in electromyographic activity, muscle fibre and force production characteristics during heavy resistance/power strength training in middle-aged and older men and women. Acta Physiol Scand 2001; 171: 51–62 25 Hakkinen K, Newton RU, Gordon SE, McCormick M, Volek JS, Nindl BC, Gotshalk LA, Campbell WW, Evans WJ, Hakkinen A, Humphries BJ, Kraemer WJ. Changes in muscle morphology, electromyographic activity, and force production characteristics during progressive strength training in young and older men. J Gerontol A Biol Sci Med Sci 1998; 53: B415–B423 26 Harridge SD, Kryger A, Stensgaard A. Knee extensor strength, activation, and size in very elderly people following strength training. Muscle Nerve 1999; 22: 831–839 27 Harriss DJ, Atkinson G. Update – ethical standards in sport and exercise science research. Int J Sports Med 2011; 32: 819–821 28 Hruda KV, Hicks AL, McCartney N. Training for muscle power in older adults: effects on functional abilities. Can J Appl Physiol 2003; 28: 178–189 29 Hunter GR, McCarthy JP, Bamman MM. Effects of resistance training on older adults. Sports Med 2004; 34: 329–348 30 Izquierdo M, Aguado X, Gonzalez R, Lopez JL, Hakkinen K. Maximal and explosive force production capacity and balance performance in men of different ages. Eur J Appl Physiol 1999; 79: 260–267 31 Jackson AS, Pollock ML. Generalized equations for predicting body density of men. Br J Nutr 1978; 40: 497–504 32 Komi PV. Stretch-shortening cycle: a powerful model to study normal and fatigued muscle. J Biomech 2000; 33: 1197–1206 33 Komi PV. IOC Medical Commission., International Federation of Sports Medicine. Strength and Power in Sport. Oxford: Blackwell Scientific, 1992

Downloaded by: Dot. Lib Information. Copyrighted material.

968 Training & Testing

34 Korhonen MT, Mero AA, Alen M, Sipila S, Hakkinen K, Liikavainio T, Viitasalo JT, Haverinen MT, Suominen H. Biomechanical and skeletal muscle determinants of maximum running speed with aging. Med Sci Sports Exerc 2009; 41: 844–856 35 Kraemer WJ, Ratamess NA. Fundamentals of resistance training: progression and exercise prescription. Med Sci Sports Exerc 2004; 36: 674–688 36 Lajoie Y, Gallagher SP. Predicting falls within the elderly community: comparison of postural sway, reaction time, the Berg balance scale and the Activities-specific Balance Confidence (ABC) scale for comparing fallers and non-fallers. Arch Gerontol Geriatr 2004; 38: 11–26 37 Laroche DP. Initial neuromuscular performance in older women influences response to explosive resistance training. Isokinet Exerc Sci 2009; 17: 197 38 LaRoche DP, Cremin KA, Greenleaf B, Croce RV. Rapid torque development in older female fallers and nonfallers: a comparison across lower-extremity muscles. J Electromyogr Kinesiol 2010; 20: 482–488 39 Laroche DP, Knight CA, Dickie JL, Lussier M, Roy SJ. Explosive force and fractionated reaction time in elderly low- and high-active women. Med Sci Sports Exerc 2007; 39: 1659–1665 40 LaRoche DP, Roy SJ, Knight CA, Dickie JL. Elderly women have blunted response to resistance training despite reduced antagonist coactivation. Med Sci Sports Exerc 2008; 40: 1660–1668 41 Macaluso A, De Vito G. Muscle strength, power and adaptations to resistance training in older people. Eur J Appl Physiol 2004; 91: 450–472 42 Malisoux L, Francaux M, Nielens H, Renard P, Lebacq J, Theisen D. Calcium sensitivity of human single muscle fibers following plyometric training. Med Sci Sports Exerc 2006; 38: 1901–1908 43 Moritani T, deVries HA. Neural factors versus hypertrophy in the time course of muscle strength gain. Am J Phys Med 1979; 58: 115–130

44 Narici MV, Roi GS, Landoni L, Minetti AE, Cerretelli P. Changes in force, cross-sectional area and neural activation during strength training and detraining of the human quadriceps. Eur J Appl Physiol 1989; 59: 310–319 45 Petrella JK, Miller LS, Cress ME. Leg extensor power, cognition, and functional performance in independent and marginally dependent older adults. Age Ageing 2004; 33: 342–348 46 Pyka G, Lindenberger E, Charette S, Marcus R. Muscle strength and fiber adaptations to a year-long resistance training program in elderly men and women. J Gerontol 1994; 49: M22–M27 47 Seynnes O, Fiatarone Singh MA, Hue O, Pras P, Legros P, Bernard PL. Physiological and functional responses to low-moderate versus highintensity progressive resistance training in frail elders. J Gerontol A Biol Sci Med Sci 2004; 59: 503–509 48 Skelton DA, Young A, Greig CA, Malbut KE. Effects of resistance training on strength, power, and selected functional abilities of women aged 75 and older. J Am Geriatr Soc 1995; 43: 1081–1087 49 Stensdotter AK, Hodges PW, Mellor R, Sundelin G, Hager-Ross C. Quadriceps activation in closed and in open kinetic chain exercise. Med Sci Sports Exerc 2003; 35: 2043–2047 50 Sturnieks DL St, George R, Lord SR. Balance disorders in the elderly. Neurophysiol Clin 2008; 38: 467–478 51 Tinetti ME. Clinical practice. Preventing falls in elderly persons. N Engl J Med 2003; 348: 42–49 52 Yamada T, Demura S. Relationships between ground reaction force parameters during a sit-to-stand movement and physical activity and falling risk of the elderly and a comparison of the movement characteristics between the young and the elderly. Arch Gerontol Geriatr 2009; 48: 73–77

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