acute and chronic cardiovascular response to 16

ACUTE AND CHRONIC CARDIOVASCULAR RESPONSE TO 16 WEEKS OF COMBINED ECCENTRIC OR TRADITIONAL RESISTANCE AND AEROBIC TRAINING IN ELDERLY HYPERTENSIVE WOMEN: A RANDOMIZED CONTROLLED TRIAL EDUARDO S. DOS SANTOS,1 RICARDO Y. ASANO,1 IREˆNIO G. FILHO,2 NILSON L. LOPES,2,3 PAULO PANELLI,2 DAHAN DA C. NASCIMENTO,1 SCOTT R. COLLIER,4 AND JONATO PRESTES1 1

Graduate Program on Physical Education, Catholic University of Brasilia, Brasilia, Brazil; 2Research Group in Exercise Physiology (GEFEFIS), North-Northeast Cardiology Institute, Bahia, Brazil; 3Dom Pedro of Alcantara Hospital, Bahia, Brazil; and 4Vascular Biology and Autonomic Studies Laboratory, Appalachian State University, Boone, North Carolina

ABSTRACT dos Santos, ES, Asano, RY, Filho, IG, Lopes, NL, Panelli, P, Nascimento, DdaC, Collier, SR, and Prestes, J. Acute and chronic cardiovascular response to 16 weeks of combined eccentric or traditional resistance and aerobic training in elderly hypertensive women: A randomized controlled trial. J Strength Cond Res 28(11): 3073–3084, 2014—Both aerobic (AT) and resistance training (RT) are recommended as nonpharmacological treatments to prevent hypertension. However, there is a paucity of literature investigating the effects of combined exercise modes (RT combined with AT) in elderly hypertensive women. Thus, our aim was to compare the postexercise hypotension (PEH) response to both protocol models and to assess the correlation between the degree of PEH after acute and chronic training. Furthermore, we also compared several biochemical variables for each training group. Sixty hypertensive older women were randomly assigned into nonexercised control (no systematic exercise training throughout the study), eccentric RT (ERT), and traditional RT (TRT). The training programs consisted of 16 weeks of RT combined with AT. Blood pressure (BP), biochemical profiles, and 1 repetition maximum (1RM) were evaluated. There was a significant increase in high-density lipoprotein (HDL) after both training regimens pre- to posttraining (combined ERT +5% and TRT +7%; p = 0.001 for both). There was a decrease in systolic BP (SBP) (combined ERT 219% and TRT 221%; p = 0.001 for both) and diastolic BP (DBP) (213% for both; p = 0.001 for both). There was an increase in bench press 1RM (combined Address correspondence to Dr. Jonato Prestes, [email protected]. 28(11)/3073–3084 Journal of Strength and Conditioning Research Ó 2014 National Strength and Conditioning Association

ERT +54% and TRT +35%; p = 0.001 for both) and leg press 1RM (combined ERT +52% and TRT +33%; p = 0.001 for both). The magnitude of decrease in SBP after acute exercise was moderately correlated with the drop in SBP after chronic training for the ERT combined with AT group (r = 0.64). Both combined training protocols are effective in promoting benefits in health-related factors (HDL, SBP, DBP, and 1RM). Considering the lower cardiovascular stress experienced during combined ERT, this type of training seems to be the most suitable for elders, deconditioned individuals, and hypertensives.

KEY WORDS blood pressure, hypertension, strength training, postexercise hypotension, cardiovascular risk factors

INTRODUCTION

H

ypertension is a complex, multifactorial disease characterized by high blood pressure (BP) levels ($140/90 mm Hg) with unknown specific underlying causes. Associated risk factors include age, overweight, insulin resistance, diabetes, race, smoking status, socioeconomic levels, and hyperlipidemia (23,33). Data from the National Center of Health Statistics (10) have shown that the age-adjusted prevalence of hypertension (both diagnosed and undiagnosed) from 2003 to 2006 was 75% for older women and 65% for older men, demonstrating that, with age, women catch and surpass men in the incidence of hypertension. Because hypertension is a key factor in the development of cardiovascular disease (CVD), which is the largest reported cause of death globally, these data punctuate the need for effective treatments. Urban Brazil is a unique location to study this disease because 68% of the elderly population present with hypertension (27). Although pharmacological therapy is commonly used to treat elderly pre- to hypertensive patients, nonpharmacological strategies, including lifestyle modifications such as VOLUME 28 | NUMBER 11 | NOVEMBER 2014 |

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Resistance Training in Elderly Hypertensive Women physical activity, have been shown to be beneficial (28). Among lifestyle modifications, guidelines predominantly recommend aerobic training (AT) for lowering BP (43), although both resistance training (RT) and AT can promote substantial benefits of physical fitness and health-related factors, such as BP, serum lipids, glucose metabolism, cardiac autonomic function, and muscular strength (8,9,18,29). Moreover, postexercise hypotension (PEH) is claimed to promote cardiovascular protection because of a significant reduction in BP during the recovery period (40,41). Interestingly, the degree of acute systolic and diastolic PEH was associated with the magnitude of resting BP reduction after 8 weeks of AT at 65% of maximum oxygen consumption. Furthermore, acute bouts of RT have been shown to elicit a greater PEH when compared with AT, which may be because of greater increases in peripheral blood flow; however, little is known regarding the potential differences in outcomes from RT training modes (6). Eccentric RT (ERT) has been shown to stimulate muscle growth and allows a higher force production compared with concentric training, maximizing the structural and functional muscle responses at the lowest metabolic cost to the individual. This is particularly interesting for frail elderly individuals with low muscular and cardiorespiratory fitness, especially because RT has also been shown to benefit individuals with osteoporosis (15). Despite the potential of RT for lowering BP (9), no randomized controlled trial has investigated the effects of ERT combined with AT on acute and chronic PEH in older hypertensive women. In addition, some parameters, such as antihypertensive medications, age, degrees of hypertension, and association between the magnitude of PEH and chronic BP reductions in response to different protocols of RT combined with AT, remain to be determined. Nevertheless, we chose a combined training for our experimental design because it has been shown to induce greater benefits for weight loss, fat loss, and cardiorespiratory fitness than AT and RT modalities alone (14,37). In addition, because some people may have difficulty finding time to exercise, it is important to combine the benefits of AT and RT. Thus, the aim of this study was twofold: (a) to compare the PEH response to ERT and traditional RT (TRT) combined with AT and (b) to assess the correlation between the degree of hypotension in response to acute exercise and the magnitude of change in resting BP. A secondary goal was to compare chronic alterations in muscular strength and biochemical profile in response to both regimens to understand the causal mechanisms involved with our findings. We hypothesized that both protocols would induce PEH and the magnitude of change (D) in BP reduction after acute exercise would correlate with the BP reduction after chronic combined training. We also expected ERT combined with AT to induce higher gains in muscular strength with similar modifications in biochemical profile when compared with TRT combined with AT.

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METHODS Experimental Approach to the Problem

This was a randomized controlled trial designed to compare the effects of combined ERT and TRT on BP and biochemical profile in elderly hypertensive women. Both training regimens included 20 minutes of AT plus whole body RT performed during 16 weeks. Independent variables were the training regimens, and the dependent variables were BP, muscular strength, and biochemical parameters. We also tested the correlation between acute BP responses and the chronic decrease in BP. Combined training was chosen because it has been shown to maximize improvements in cardiovascular and health-related biochemical parameters. Moreover, ERT was included because of its proposed suitability for frail and diseased individuals. Subjects

A total of 60 elderly female patients age 60–65 years with essential hypertension were recruited and randomly assigned to 1 of the 3 experimental groups: TRT combined with AT, ERT combined with AT, or a nonexercised control group with no systematic exercise training throughout the study (C). Each patient completed a thorough physical examination including a medical history screening, resting and exercise electrocardiogram, manual BP measurement and anthropometric and orthopedic evaluation before participation in the study. All patients were classified with hypertension stage 1 or 2 according to the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure (4) and were evaluated by an experienced cardiologist. Participants were classified as sedentary and untrained according to the International Physical Activity Questionnaire (22) and the American College of Sports Medicine guidelines (2). Subjects with physical disabilities, diagnosis of diabetes, CVDs, hypertension (systolic blood pressure [SBP] .180 mm Hg and diastolic blood pressure [DBP] .110 mm Hg), musculoskeletal disease, or who smoked or abused drugs/alcohol were excluded from the trial. This study was approved by the Institutional Ethics Committee of the Catholic University of Brası´lia (protocol 253/11) and conformed to the Helsinki Declaration on the use of human subjects for research. All subjects were informed of the procedures and provided a written informed consent to participate in the study. Protocol

A randomized controlled trial study was carried out. Initially, participants completed medical, anthropometric, body composition, and hemodynamic evaluations and 2 weeks of familiarization to the exercises. After the familiarization period, participants completed the 10 repetitions maximum (10RM) testing in each exercise and were randomly assigned to TRT or ERT combined with AT with 3 sessions per week for 16 weeks. The hemodynamic parameters were evaluated pre-exercise, 15, 30, 45, and 60 minutes after the first and last

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Journal of Strength and Conditioning Research training session. All sessions were performed at the same period of the day (between 10 AM and noon) to avoid any influence of the circadian rhythm on the measured cardiovascular variables. Familiarization and One Repetition Maximum and Ten Repetitions Maximum Tests

To avoid any influence of anxiety on BP and to ensure proper exercise form, all study participants completed 2 weeks of familiarization before the beginning of the training programs, consisting of 1 exercise for each main muscle group with sets of 10–12 submaximal repetitions at 70% of estimated 10RM with 1-minute rest intervals between sets and exercises. In this period, individuals were advised regarding proper RT technique. After the familiarization period, 1RM tests were performed on 2 different days separated by a minimum of 72 hours. All tests were performed with 10-minute rest intervals between each exercise. The testing order for the 458 leg press and barbell bench press RT exercises was random. The protocol consisted of a light warm-up of 10 minutes of treadmill walking followed by 8 repetitions at 50% of estimated 1RM (according to the participants’ capacity verified in the 2 weeks of familiarization). After a 1-minute rest, subjects performed 3 repetitions at 70% of the estimated 1RM. After 3 minutes of rest, participants completed 3–5 attempts interspersed with 3- to 5-minute rest intervals, with progressively heavier weights (;5%) until the 1RM was determined. A high intraclass correlation coefficient (ICC) was found for both exercises (R = 0.98). The range of motion and exercise technique were standardized according to the descriptions of Tibana et al. (40). During the following week, 10RM tests and retests were performed to determine the exact training load for each exercise on 2 nonconsecutive days with 72 hours between tests. The 10RM tests were randomly performed to avoid an effect of exercise order for the following exercises: barbell bench press, 458 leg press, trunk extension, leg extension, arm curl, dorsiflexion, and lateral raise (Johnson, Cottage Grove, WI, USA). Before testing, subjects walked at a low intensity for 5 minutes on a treadmill. The 10RM testing procedures progressed as follows: (a) warm-up on each exercise with 5–10 submaximal repetitions using a light load (60% of the predicted 10RM); (b) 1-minute rest and load increments of 5–10% until the 10RM was found within 3–5 attempts, using 3- to 5-minute rest intervals between them; (c) subjects were instructed to lift and lower the load at a constant velocity, taking approximately 2 seconds for each phase of the movement; (d) 10 repetitions were recorded, with the maximal load determined by the last successful set of repetitions, with individual supervision (42). Test/retest reliability for the 10RM was performed and a high ICC was found (R = 0.98) for all tested exercises. The following strategies were adopted to minimize testing errors: (a) all subjects participated in a familiarization period before testing; (b) standardized instructions were provided to all subjects before the tests; (c) subjects were carefully

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instructed about maintaining proper exercise technique and body position; (d) consistent verbal encouragement was provided during the testing procedures to all subjects. All testing sessions were scheduled between the hours of 10:00 AM and noon to avoid diurnal variation. Combined Resistance and Aerobic Training Programs

The selection of the periodization programs was based on the results of previous investigations (25,30,36). Participants initiated the training 72 hours after the 10RM tests and completed 3 weekly training sessions for 16 weeks on Mondays, Wednesdays, and Fridays. Traditional RT was performed as follows: weeks 1–5 at 70% of 10RM, weeks 6–11 at 80% of 10RM, and weeks 12–16 at 90% of 10RM, always performing 3 sets of 10 repetitions. The mean duration to complete 1 repetition was 3–4 seconds (both concentric and eccentric phases of the movement), whereas in the ERT the duration was 2–3 seconds. Loads for 10RM were updated every 4 weeks. Submaximal loads were chosen to avoid the exacerbation of the hemodynamic response and/or Valsalva maneuver, as there were no clinical intercurrences throughout the training period in these hypertensive women (35). Progression for the ERT group was as follows: weeks 1–5 at 100% of 10RM, weeks 6–11 at 110% of 10RM, and weeks 12–16 at 120% of 10RM with 3 sets of 10 eccentric repetitions. During ERT, the concentric phase of the movement was completed by the strength and conditioning professional, and the subject was only allowed to perform the eccentric action. Training sessions lasted approximately 50–60 minutes, and cardiovascular parameters were monitored during this time. No clinical outcomes during exercise sessions were reported. Resistance exercises for both training programs were barbell bench press, 458 leg press, trunk extension, leg extension, arm curl, dorsiflexion, and lateral raise. Rest intervals were fixed at 60 seconds between sets and 90 seconds between exercises. After each RT session, individuals completed 20 minutes of AT on a treadmill (Movement-PRO 150, Sao Paulo, Brazil) at 65–75% of their estimated target heart rate (THR) as determined by the equation: THR = % (HRmax 2 HRrest) + HRrest (17), where % = selected work percentage, HRmax = maximal heart rate, and HRrest = resting heart rate. Heart rate (HR) was monitored in all training sessions using a HR monitor. The estimated HRmax was calculated by the equation: HRmax = 208 2 (0.7 3 age) (39). Hemodynamic Measurements

The SBP, DBP, and pulse pressure (PP) were measured and calculated with an oscillometric device (Microlife 3AC1-1, Widnau, Switzerland) according to the recommendations of the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure (4). The cuff size was adapted to the circumference of the arm of each patient according to the manufacture’s recommendations. Heart rate was measured using a HR monitor (Polar S810i; Polar Electo Oy, Kempele, Finland). VOLUME 28 | NUMBER 11 | NOVEMBER 2014 |

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Resistance Training in Elderly Hypertensive Women All BP measures were assessed in triplicate (measurements separated by 1 minute; r = 0.98 for all measures) with the mean value used for analysis. The hemodynamic measurements were performed after 10 minutes of seated rest and at 15, 30, 45, and 60 minutes (times 1, 2, 3, and 4, respectively) after the control or exercise sessions. The acute response was analyzed in the first training session after familiarization to RT and strength tests, whereas the chronic hypotension was measured after the last training session. All measures of BP were taken during 10 AM to noon to minimize diurnal BP variability. During BP measurements, participants remained seated quietly under a controlled room temperature. Participants were advised to maintain their habitual activities and diet (this was guaranteed by a dietary recall follow-up), refrain from programmed exercise, and avoid smoking, alcohol and caffeine consumption.

sured by the Automation Method. The turbidimetric method with particles intensification reaction was used to measure C-reactive protein with a spectrophotometer Cobas Mira Plus (Roche Diagnostic, GmBH, Mannheim, Germany), calibrator and control serum Biosystem (Bayer Diagnostics, Emeryville, CA, USA). Creatinine was determined by the kinetic enzymatic method by using the same spectrophotometer. Statistical Analyses

Considering a power of 85% and an alpha error of 0.05 and assuming a standard deviation of 5 mm Hg, the sample size necessary to detect a mean decrease of 4 mm Hg in SBP and DBP was calculated to be 60 individuals. For analyses of normality and homogeneity, the Shapiro-Wilk and Levene tests were used, respectively. To examine the response of the biochemical and hemodynamic variables to the chronic exercise intervention, an analysis of variance (ANOVA) (3 3 2, groups 3 moments [pre- and post-16 weeks]) was used. For the strength variable 1RM, an ANOVA (2 3 2, group 3 moments [pre- and post-16 weeks]) was performed, and for the area under the curve (AUC) hemodynamic variables, an ANOVA (3 3 4, groups 3 time [time 1, time 2, time 3, and time 4]) was conducted (1). When differences were indicated between groups and moments, post hoc comparisons were applied (11,12). For effect size calculation, the following formula was applied: (pretest mean 2 posttest mean)/mean of both SD (12). For determination of the magnitude of effect sizes, we considered the following values for untrained individuals: trivial (,0.50), small (0.50–1.25), moderate (1.25– 1.9), and large (.2.0) (34). To calculate the variations within individuals, the coefficient of variation was used: CV% = (SD/mean) 3 100.

Anthropometric and Body Composition Evaluation

Height and weight were measured and allowed the calculation of the body mass index. All circumferences were obtained in triplicate using a nonelastic tape measure and averaged to determine the final reported circumference. Body adiposity index (BAI) was determined by the following formula: BAI = (hip circumference)/([height 3 1.5] 2 18) (3). Biochemical Parameters

Biochemical parameters were measured before and after 16 weeks of training. Briefly, participants reported to the laboratory between 08:00 and 10:00 AM, after an overnight fast, for blood withdrawal from the antecubital vein. Plasma triglycerides and glucose levels were measured by enzymatic CHOP-POD and Hexokinase methods, respectively. Total cholesterol, high-density lipoprotein (HDL), and LDL were mea-

TABLE 1. Subject characteristics.* Variables

C (N = 20)

Age (y) Body mass (kg) Height (m) Body mass index (kg$m22) Body adiposity index (%) Waist (cm) Hip (cm) Neck (cm) Waist-to-hip ratio Systolic blood pressure (mm Hg) Diastolic blood pressure (mm Hg) Medications (%) Angiotensin-converting enzyme inhibitors Angiotensin receptor blockers Dihydropyridine calcium channel blockers

63.1 69.87 1.55 28.98 29.96 94.55 100.05 33.99 0.97 160.70 89.85

(2.3) (11.90) (0.04) (4.36) (5.66) (9.24) (13.84) (3.63) (0.25) (9.12) (4.81)

9 6 4

ERT (N = 20) 64.2 66.51 1.54 27.79 24.21 93.35 97.70 34.51 0.95 162.70 85.50

(3.1) (13.93) (0.05) (4.73) (2.61) (11.56) (6.76) (2.55) (0.07) (7.81) (4.26)†

6 5 8

TRT (N = 20) 62.6 67.21 1.53 28.47 26.59 93.80 102.55 34.35 0.91 163.05 88.80

(2.5) (11.18) (0.05) (4.40) (4.59) (10.40) (9.77) (2.80) (0.08) (4.43) (3.60)

5 10 5

*Data are expressed by means and SD. N = sample number; C = control group; TRT = traditional resistance training; ERT = eccentric resistance training. †Significantly different from the C group and TRT (#0.05).

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TABLE 2. Blood pressure and muscle strength at baseline and 16-week follow-up.* SBP (mm Hg)

Control group CV% ES ERT group CV% ES TRT group CV% ES

DBP (mm Hg)

PP (mm Hg)

PRE

Post

PRE

Post

PRE

Post

160.70 (9.13) 2.68 0.14 166.05 (8.06) 4.85 2.48 167.60z (4.31) 2.57 4.24

162.55† (8.94) 5.50

89.85 (4.82) 5.36 0.04 90.15 (4.26) 4.72 1.84 91.25 (3.55) 3.89 2.35

90.10 (4.53) 5.03

70.85 (9.66) 13.65 0.11 75.90 (7.76) 10.22 1.59 76.35 (5.05) 6.61 2.51

72.45† (9.86) 13.61

135.20†z (8.80) 6.51 132.50†z§ (7.96) 6.01

78.30†z§ (4.39) 5.61 79.20†z (3.17) 4.01

Bench press (kg)

53.30†z§ (8.27) 15.51

458 leg press (kg) Post

PRE

Post

15.90 (1.48) 9.33 3.48 16.20 (1.28) 7.91 2.99

24.05†z§ (1.72) 7.17

69.00 (4.21) 6.09 5.82 68.25 (5.40) 7.91 2.68

105.15†z§ (4.00) 3.81

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PRE


21.88† (1.23) 5.64

90.80† (6.04) 6.65

*Data are expressed by means and SD. TRT = traditional resistance training; ERT = eccentric resistance training; SBP = systolic blood pressure; DBP = diastolic blood pressure; PP = pulse pressure; CV = coefficient of variation; ES = effect size. †Differences within groups pre vs. post (#0.05). zDifferences between eccentric vs. control at the same time point (#0.05); differences between traditional vs. control at the same time point (#0.05); differences between eccentric vs. traditional at the same time point (#0.05). §Significant exercise group 3 time interaction (#0.05).

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Resistance Training in Elderly Hypertensive Women

Figure 1. Representation of the area under the curve (AUC) for SBP and diastolic blood pressure (DBP). zLower than control group at the same time point (,0.05); †lower than pretraining values (time 1) (,0.05) time 1, 15 minutes after exercise; time 2, 30 minutes after exercise; time 3, 45 minutes after exercise; time 4, 60 minutes after exercise.

The change in BP after acute exercise was calculated using 2 methods: (a) magnitude of BP was determined as the difference between pre-exercise BP and the lowest BP in the postexercise time period; (b) AUC quantified the difference between pre-exercise BP and postexercise BP during a period of 60 minutes. The trapezoidal method was used by dividing the postexercise period into 4 moments (time 1, time 2, time 3, and time 4) and summing the values as indicated in the following formula (31):

. AUCðmm Hg$min21 Þ ¼ ðm0 þ m1 Þ3t1 2 . þ ðm1 þ m2 Þ3t2 2 . þ ðm2 þ m3 Þ3t3 2 . þ ðm3 þ m4 Þ3t4 2:

Adherence to the training sessions was determined by dividing the number of exercise sessions completed by the total number of exercise sessions. Linear regression analyses were used to assess the relationship between the change in BP reduction after acute and chronic exercise. Correlation coefficient values between 60.1 and 6 0.3, 60.4 and 6 0.6, and .0.7 were considered weak, moderate, and strong, respectively (12). An alpha level of #0.05 was considered significant, and p values presented are 2-sided. Data are reported as mean 6 SD. All analyses were conducted with SPSS version 18.0 (SPSS, Inc., Chicago, IL, USA).

RESULTS

From 75 recruited participants, only 60 subjects completed the study. The individuals who did not complete the study were disqualified because they failed to meet the study’s inclusion criteria for age (n = 6), resting BP (n = 4) or medical history (n = 3), or they declined because of personal reasons (n = 2). The adherence to the training sessions was .95%. TABLE 3. Hypotension after acute and chronic exercise.* There were no adverse cardioAcute exercise Posttraining vascular responses to exercise testing or training. No modificaControl tions for medications (doses, DSBP (mm Hg) 0.21 (0.59) 0.31 (0.64) DDBP (mm Hg) 0.89 (0.91) 0.77 (1.17) types, etc.) were observed over Eccentric resistance training the 16-week program. Subject DSBP (mm Hg) 24.01 (0.37)† 26.94 (0.2)†z§ characteristics are summarized DDBP (mm Hg) 24.93 (0.98)† 212.03 (1.23)†z§ in Table 1. There was no signifTraditional resistance training icant difference between the DSBP (mm Hg) 22.52 (0.38)† 24.17 (0.57)†§ DDB (mm Hg) 24.17 (0.57)† 28.12 (1.10)†§ groups for body mass (F(2.57), 0.40, p = 0.66), height (F(2.57), *Data are expressed by mean and SD. SBP = systolic blood pressure; DBP = diastolic 0.45, p = 0.63), body mass index blood pressure. †Differences between traditional and eccentric vs. control at the same time point (,0.01). (F(2.57), 0.34, p = 0.70), zSignificant exercise group 3 time interaction (,0.01). BAI (F(2.57), 1.47, p = 0.23), §Differences within groups pre vs. post (,0.01). waist (F(2.57), 0.06, p = 0.93), hip (F(2.57), 1.06, p = 0.35),

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Figure 2. The magnitude of change in systolic blood pressure (SBP) and diastolic blood pressure (DBP) after acute and chronic exercise. The magnitude of change (D) in SBP after acute exercise was significantly correlated with the magnitude of change in resting SBP after chronic exercise for the eccentric group (r = 0.64, p = 0.002, 0.9 6 0.253 [b 6 SE]). For the other analyses, the magnitude of changes in SBP and DBP after acute exercise was not significantly correlated with the magnitude of changes in resting SBP and DBP after chronic exercise.

neck circumferences (F(2.57), 0.15, p = 0.85), waist-to-hip ratio (F(2.57), 0.64, p = 0.52), and SBP (F(2.57), 0.58, p = 0.55). The combined ERT group presented a lower DBP when compared with C and TRT groups (F(2.57), 5.6, p = 0.006). Hemodynamic Variables

There were significant group 3 time interactions for SBP (Table 2). Both combined TRT (F(2.57) = 75.17, p = 0.001) and ERT (F(2.57) = 75.17, p = 0.001) groups decreased SBP after 16 weeks as compared with the C group. Additionally, combined ERT (t(19) = 34.01, p = 0.001) and TRT (t(19) = 23.75, p = 0.001) groups decreased SBP after 16 weeks as compared with the pre-intervention value, whereas the control group presented an increase of SBP after 16 weeks as compared with initial values (t(19) = 5.28, p = 0.001). There was a more pronounced drop in SBP for the combined TRT group (F(2.114) = 63.32, p = 0.001) as compared with ERT. Group 3 time interactions were also found for DBP and PP, as both combined TRT (F(2.57) = 51.92, p = 0.001;

F(2.57) = 26.32, p = 0.001, respectively) and ERT groups (F(2.57) = 51.92, p = 0.001; F(2.57) = 26.32, p = 0.001, respectively) displayed lower values of DBP and PP as compared with the C group. Moreover, combined TRT (t(19) = 46.62, p = 0.001; t(19) = 13.73, p = 0.001, respectively) and ERT groups (t(19) = 29.60, p = 0.001; t(19) = 19.79, p = 0.001, respectively) decreased DBP and PP posttraining as compared with pre-intervention. The combined ERT group exhibited a more pronounced drop in DBP as compared with the TRT group (F(2.114) = 28.68, p = 0.001). However, combined TRT induced a higher drop in PP (F(2.114) = 25.25, p = 0.001) vs. ERT. Area Under the Curve: Acute Exercise

For DBP, the combined ERT (F(2.57) = 30.59, p = 0.001) and TRT groups (F(2.57) = 30.59, p = 0.001) revealed lower values at time 2 when compared with the C group. There were differences within groups at the time 3 for SBP and DBP, as indicated by the lower values at time 3 compared VOLUME 28 | NUMBER 11 | NOVEMBER 2014 |

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TC (mg$dl21)

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LDL (mg$dl21)

CRP (U$L21)

PRE

Post

PRE

Post

PRE

Post

PRE

Post

201.30 (23.30) 11.58 0.14 209.50 (27.31) 13.04 0.42 211.65 (20.20) 9.54 0.48

206.50 (29.97) 14.51

129 (38.46) 29.81 0.03 149.25 (26.22) 17.57 0.22 148.60 (34.40) 23.15 0.20

130 (38.21) 29.20

141.75 (36.51) 25.75 0.05 156.15 (38.15) 24.43 0.22 157.45 (33.11) 21.03 0.21

144.35 (34.10) 23.62

0.61 (0.22) 36.47 0.29 0.80 (0.36) 44.86 0.20 0.87 (0.38) 43.79 0.12

0.77 (0.61) 80.01

193.70 (20.99) 10.84 195.80 (25.77) 12.90 Glucose (mg$dl21)


TG (mg$dl21)

140.85 (23.25) 16.51 139.10 (27.97) 20.11

143.95 (32.76) 22.75 147.60 (27.83) 18.86

Creatinine (mg$dl21)

0.69 (0.35) 51.09 0.78 (0.37) 46.69

HDL (mg$dl21)

PRE

Post

PRE

Post

PRE

Post

86.50 (20.65) 23.87 0.06 90.90 (12.55) 13.80 0.47 91.80 (13.97) 15.22 0.34

88.20 (20.12) 22.81

0.74 (0.12) 16.64 0.14 0.70 (0.13) 18.53 0.25 0.82§ (0.09) 10.61 0.36

0.77 (0.11) 14.24

52.75 (4.89) 9.26 0.15 50.60 (3.50) 6.92 0.38 51.70 (6.74) 13.03 0.41

54.30 (11.01) 20.27

83.25 (7.49) 9.00 85.40 (9.48) 11.10

0.65† (0.13) 19.98 0.78§ (0.07) 8.86

53.25z (3.64) 6.84 55.45z (4.80) 8.65

*Data are expressed by mean and SD. TRT = traditional resistance training; ERT = eccentric resistance training; TC = total cholesterol; LDL = low-density lipoprotein; TG = triglycerides; HDL = high-density lipoprotein; CRP = C-reactive protein; ES = effect size; CV = coefficient of variation. †Differences between eccentric vs. control group at the same time point (#0.05). zDifferences within groups pre vs. post (#0.05). §Differences between traditional vs. eccentric at the same time point (#0.05).


Resistance Training in Elderly Hypertensive Women

3080 TABLE 4. Biochemical parameters at baseline and 16-week follow-up.*

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Journal of Strength and Conditioning Research with time 1 for combined TRT and ERT groups (F(3.228) = 3.06, p = 0.029). For the SBP at time 3, the combined ERT group (F(2.57) = 4.50, p = 0.015) demonstrated lower values when compared with C group, but no differences were found between TRT and C groups. Additionally, DBP displayed lower values for the combined ERT (F(2.57) = 38.10, p = 0.001) and TRT groups (F(2.57) = 38.10, p = 0.001) at time 3 when compared with the C group. At time 4, the combined ERT group (F(2.57) = 3.29, p = 0.039) demonstrated lower values of SBP when compared with C group, but no differences were found between TRT and C groups. The combined ERT (F(2.57) = 30.31, p = 0.001) and TRT groups (F(2.57) = 30.31, p = 0.001) demonstrated lower DBP at the time 4 when compared with the C group (Figure 1). Area Under the Curve: Chronic Exercise

There were differences between groups at time 2 for SBP and DBP, which were revealed by the lower values of SBP and DBP for the combined ERT (F(2.57) = 79.86, p = 0.001; F(2.57) = 30.31, p = 0.001, respectively) and TRT groups (F(2.57) = 79.86, p = 0.001; F(2.57) = 30.31, p = 0.001, respectively) as compared with C group (Figure 1). Systolic BP was decreased at time 3 vs. time 1 for the combined TRT and ERT groups (F(3.228) = 3.10, p = 0.027). Diastolic BP was decreased at time 2, time 3, and time 4 vs. time 1 for the combined TRT and ERT groups (F(3.228) = 5.77, p = 0.001). Moreover, DBP was reduced at time 3 for the combined ERT (F(2.57) = 129.52, p = 0.001) and TRT groups (F(2.57) = 129.52, p = 0.001) as compared with the C group. A difference between groups was also found at time 4, revealed by the decreased values of SBP and DBP for the combined ERT (F(2.57) = 86.64, p = 0.001; F(2.57) = 127.40, p = 0.001, respectively) and TRT groups (F(2.57) = 86.64, p = 0.001; F(2.57) = 127.40, p = 0.001) as compared with the C group (Figure 1). Group 3 time interactions were also found for the magnitude of decrease in SBP and DBP (F(2.114) = 84.79, p = 0.001; F(2.114) = 116.60, p = 0.001, respectively), as both combined TRT and ERT groups (F(2.57) = 437.30, p = 0.001; F(2.57) = 211.28, p = 0.001, respectively) displayed lower values of SBP and DBP as compared with the C group both pre- and postintervention. Moreover, combined TRT and ERT groups (t(19) = 11.80, p = 0.001; t(19) = 32.99, p = 0.001, respectively) decreased SBP and DBP posttraining as compared with pre-intervention. There was a type of training effect on SBP and DBP, revealed by the most pronounced drop observed for the combined ERT group as compared with the TRT group (F(2.114) = 84.79, p = 0.001; F(2.114) = 116.60, p = 0.001, respectively; Table 3). The greatest reduction in DSBP after acute exercise was moderately correlated with the chronic reduction in DSBP (r = 0.64, p = 0.002; Figure 2) only for the combined ERT group. There were no additional correlations for the acute changes in DSBP and DDBP with the magnitude of changes in resting SBP and DBP after chronic exercise (p . 0.05; Figure 2).

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Muscular Strength

There were group 3 time interactions for bench press and 458 leg press 1RM, as combined ERT (t(19) = 55.99, p = 0.001; t(19) = 78.51, p = 0.001, respectively) and TRT groups (t(19) = 44.65, p = 0.001; t(19) = 47.65, p = 0.001, respectively) increased muscular strength as compared with pretraining values, although the combined ERT increased by a higher amount as compared with the TRT group (t(38) = 4.58, p = 0.001; t(38) = 8.85, p = 0.001, respectively; Table 2). Biochemical Response to Chronic Exercise

There were no training effects or group 3 time interactions on total cholesterol, LDL, TG, C-reactive protein, and glucose (p . 0.05; Table 4). There were differences between groups for creatinine, where the combined ERT group demonstrated lower values than the C group (F(2.57) = 8.23, p = 0.005) and TRT (F(2.57) = 8.23, p = 0.002) after 16 weeks. Additionally, the combined TRT group demonstrated higher values of creatinine as compared with the ERT before the intervention (F(2.57) = 5.53, p = 0.006). There was a difference within groups for HDL, indicating that both training regimens induced an increase in HDL after 16 weeks (ERT [t(19) = 24.7, p = 0.001] and TRT [t(19) = 25.07, p = 0.001]).

DISCUSSION To the best of our knowledge, this is the first study to compare the acute and chronic effects of TRT and ERT protocols combined with AT on BP, biochemical variables, and muscular strength in older hypertensive women. We also investigated the correlation between the degree of PEH with acute exercise and the magnitude of change in resting BP after chronic training. The greatest finding of the study was that both RT protocols induced a decrease in SBP, DBP, and PP, whereas only the ERT combined with AT group exhibited a correlation between the acute hypotension and the chronic decrease of SBP. Moreover, both training regimens improved HDL levels, whereas only the ERT combined with AT group decreased creatinine values as compared with the control group. There was also an increase in upper- and lower-body muscular strength, with superior results for the combined ERT group. In this study, SBP, DBP, and PP were reduced following both chronic TRT and ERT protocols combined with AT in hypertensive older women. This is in accordance with previous studies (9,38), demonstrating that dynamic RT combined with AT can lower BP and also be used as prevention against stroke (20). Mota et al. (24) found that a whole-body RT program consisting of 3 sets of 8–12 repetitions at 60–80% of 1RM resulted in a significant PEH in elderly hypertensive women during the second, third (SBP), and fourth (DBP) months of training. Additionally, resting BP was significantly reduced after 16 weeks of training. However, Mota et al. (24) used only TRT, whereas this study compared combined TRT with combined ERT. Our data reinforce that combined ERT can be used as a safe RT VOLUME 28 | NUMBER 11 | NOVEMBER 2014 |

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Resistance Training in Elderly Hypertensive Women method to chronically decrease BP in elderly hypertensive women. Interestingly, it has been proposed that ERT provides more intense muscular work achieved at a lower metabolic expense, yielding a more efficient workout (19) while providing a powerful tool for restoring muscular strength in people with a limited capacity to train at high intensities such as older adults. Furthermore, Reeves et al. (32) investigated 9 older adults (74 6 3 years) assigned to a TRT protocol performing both concentric and eccentric contractions and 10 older adults (67 6 2 years) assigned to an ERT protocol. Both groups trained 3 times per week for 14 weeks, at 80% of their 5RM, specific to each training mode. Although ERT was performed with heavier absolute loads, ratings of perceived exertion were consistently lower along training weeks as compared with TRT. We observed that the magnitude of SBP reduction after acute exercise (post-acute exercise first week) was correlated with the magnitude of SBP reduction after 16 weeks of combined ERT (Figure 2). Liu et al. (21) have shown that the magnitude of the acute SBP- and DBP-lowering with exercise correlated with the extent of SBP- and DBPlowering after 8 weeks of a walking/jogging training program (4 times per week, 30 minutes per session, 65% maximum oxygen consumption) in prehypertensive individuals. In addition, Collier et al. (7) have shown that sex differences exist in the BP lowering effects of resistance exercise and that women reap the benefits of lowering their BP without any deleterious effects such as arterial stiffening. These results reinforce the idea that both RT and AT can promote substantial benefits on BP in older hypertensive women. Our results have important clinical implications in the management of hypertension and suggest that individuals with a greater acute peak decrease in BP experience a larger total effect, which suggests that a short-term change in BP after a single bout of combined ERT could be a predictor of health-related efficacy, similar to previous studies with AT protocols (13,21). Additionally, the acute reduction in BP after the last training session was higher in the combined ERT group when compared with the combined TRT group. Thus, the specificity of a combined RT protocol, muscle actions, and intensity might have contributed to this different behavior in BP. However, because of the lack of a mechanistic approach, the explanation of specific physiological pathways responsible for the BP reduction is beyond the scope of this study. Possible explanations would be the faster adaptations experienced during combined ERT, as it has been shown that strength gains can occur after 7 days of ERT at relatively low intensity and cardiovascular demand, reinforcing the suitability of this type of training for the elderly individuals deconditioned as a result of an injury and the chronically diseased (16). Considering that strength declines with aging and that this process is associated with numerous disability processes and metabolic disturbances, such as increased fall risk, difficulty in performing daily living activities, BP elevation, and

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dyslipidemia (5), our results contribute to the body of evidence indicating that older adults can substantially increase their strength after both combined TRT and ERT. One novel finding of this study is the comparison of different protocols of combined RT (TRT vs. ERT), which has shown the combined ERT group demonstrated larger effect sizes and significantly higher strength values for the upper and lower extremities when compared with TRT, although both were effective in increasing strength values. Similarly, Reeves et al. (32) verified that eccentric knee extensor torque (measured in an isokinetic dynamometer) increased by a higher amount in the ERT vs. TRT in elderly subjects. Again, this suggests the usefulness of ERT combined with AT as an efficient tool to counteract age-related decline in muscular strength. In agreement with Peterson et al. (26), from a public health perspective, these results confirm the value of whole-body RT combined with AT for the prevention or treatment of age-related declines in muscle function and metabolic disturbances, as we also observed reductions in creatinine and elevations in HDL. To note, an important strength of this study was that diet was controlled by a dietary recall follow-up and that we had a control group, guaranteeing the effect of combined RT on the BP reduction. However, the lack of an AT only group does not allow us to make any conclusions regarding the isolated effects of RT. Another limitation of this study was the lack of control of antihypertensive medication dosage. Finally, during ERT, some resistance exercises will require the assistance of a spotter to complete the concentric phase of the movement, which may limit the use of this training method.

PRACTICAL APPLICATIONS Our results suggest that both RT protocols combined with AT were effective in improving HDL levels and reducing BP after 16 weeks, and that the reduction of SBP after acute exercise was correlated with the magnitude of change in BP after chronic RT only in the eccentric protocol. Considering the superior improvement in upper- and lower-body strength for the ERT and the improvement in BP, the use of ERT combined with AT proved to be safe and effective in elderly hypertensive women. Thus, strength and conditioning professionals should advise elderly clients to perform ERT. However, supervision is an important issue to avoid excessive loads in frail populations. Moreover, when performing ERT with traditional weight training machines and free weights, a spotter is required to lift the weight during the concentric phase of the movement. Some resistance exercises can facilitate this process; for example, in the chest press, individuals can perform the concentric phase by pressing a device with their feet, or in the leg press one can push the knees with the hands for the concentric and complete only the eccentric movement. Additional randomized controlled trials are required to elucidate the mechanisms responsible for these results in elderly and other populations, such as metabolic syndrome, obese, and diabetic subjects.

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Journal of Strength and Conditioning Research ACKNOWLEDGMENTS The authors have no financial, consultant, institutional, or other relationships that might lead to bias or a conflict of interest. The results of this study do not constitute endorsement of the product by the authors or the NSCA. All the authors contributed to the study design, data collection, and article preparation.

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