A Novel Assessment Technique Does Not Produce More Reliable Estimates of Maximal Neuromuscular Strength.

Accurate determinations of individuals' one-repetition maximum (1RM) are critical when evaluating the effectiveness of an exercise intervention involving progressive resistance training (RT). Traditional ("bottom-up"; BT) testing methods involve progressions from low to maximal loads and are commonly used in clinical and laboratory environments. Concerns about the reliability of BT testing in certain populations suggest a different technique may be more effective. Purpose: To compare the reliability and effectiveness of traditional 1RM testing to a novel technique (TDT) involving progressive load reductions and a starting intensity equal to 130% of exercisers' estimated 1RM. Method: 70 healthy adults (age = 45.03 ± 25.64 y) with diverse RT experience were randomized into a reliability testing trial (RTT; n = 33) or an optimal method trial (OMT; n = 37). Subjects in the RTT performed either TDT or BT on 3 occasions separated by ≥ 72 hours, while subjects in the OMT performed each method once in random order on separate days. Results: No significant differences in percent coefficient of variation were observed between BT and TDT for either exercise used in the study (pneumatic seated chest press: Hedge's g = 0.25, p = .49; pneumatic recumbent leg press: Hedge's g = 0.12, p = .74). TDT was not found to produce significantly higher 1RM values than BT in any group. Conclusion: TDT does not appear to facilitate more reliable 1RM estimates than BT. Further research is needed to determine the stability of these findings across levels of exercisers' age, sex, and previous RT experience.

Power vs strength training to improve muscular strength, power, balance and functional movement in individuals diagnosed with Parkinson's disease.

BACKGROUND: Declines in strength and power are cardinal symptoms of Parkinson's disease (PD), a progressive neuromuscular disorder. Progressive resistance training (PRT) has been shown to reduce a wide variety of PD-related motor deficits; however, no study has examined differences between the two most common RT methodologies utilized in this population, high-load, low velocity strength training (ST) and low-load, high-velocity power training (PT). The primary purpose of this study was to compare the effects of ST and PT on measures of strength, power, balance and functional movement in persons with PD. METHOD: Thirty-five persons with mild to moderate PD (Hoehm and Yahr Stages = 1-3; UPDRS Part III = 30.6 ±â€¯14.0) were randomized into either a ST or PT group involving 12 weeks of supervised PRT (2 visits per week). Leg press (LP) and chest press (CP) muscular strength (1RM) and muscular peak power (PP) were assessed before and after the twelve week training period as primary outcome measures. In addition, secondary measures of balance (Berg Balance Assessment (BBA), dynamic posturography (DMA), Modified Falls Efficacy Scale (MFES)), functional movement (timed up-and-go), and quality of life (PDQ-39 summary index and Mobility subscore) were obtained at the same time points, given the impact of PD symptoms on fall probability and independence. RESULTS: Repeated measures ANCOVA revealed significant improvements in LP 1RM (Mdiff = 54.89 kg, 95% CI: 43.38, 66.40; p < .05; d = 3.38) and CP 1RM (Mdiff = 7.33 kg, 95% CI: 4.75, 9.91; p < .05; d = 2.02). Additionally, significant improvements were seen in LPPP (Mdiff = 112.27 W, 95% CI: 56.03, 168.51; p < .05; d = 1.42) and CPPP (Mdiff = 52.1 W, 95% CI: 23.38, 80.86; p = .001; d = 1.29). No significant improvements were seen for any secondary outcome measures, however BBA scores were shown to significantly decrease following the intervention (Mdiff = -1.686, 95% CI: -2.89, -0.482; p = .007 d = -0.96), although this change did not reach clinical significance (clinically meaningful change = ±4.0). In addition, the ST group demonstrated significantly poorer PDQ-39SI scores (Mdiff = 4.96, 95% CI: 0.54, 9.38; p = .029), whereas the entire sample showed significantly poorer PDQ-39MOB scores (Mdiff = 4.80, 95% CI: 0.17, 9.43; p = .043; d = 0.71). CONCLUSIONS: Both ST and PT appear to be effective at reducing the neuromuscular deficits associated with PD; however, the use of these interventions for improving functional performance was not supported.

Hemodynamic responses to an exercise stress test in Parkinson's disease patients without orthostatic hypotension.

The presence of postganglionic sympathetic denervation is well established in Parkinson's disease (PD). Denervation at cardiac and blood vessel sites may lead to abnormal cardiovascular and hemodynamic responses to exercise. The aim of the present investigation was to examine how heart rate (HR) and hemodynamics are affected by an exercise test in PD patients without orthostatic hypotension. Thirty individuals without orthostatic hypotension, 14 individuals with PD, and 16 age-matched healthy controls performed an exercise test on a cycle ergometer. Heart rate, blood pressure, and other hemodynamic variables were measured in a fasted state during supine rest, active standing, exercise, and supine recovery. Peak HR and percent of age-predicted maximum HR (HRmax) achieved were significantly blunted in PD (p < 0.05, p < 0.01). HR remained significantly elevated in PD during recovery compared with controls (p = 0.03, p < 0.05). Systolic, diastolic, and mean arterial pressures were significantly lower at multiple time-points during active standing in PD compared with controls. Systemic vascular resistance index (SVRI) decreased significantly at the onset of exercise in PD, and remained significantly lower during exercise and the first minute of supine recovery. End diastolic volume index (EDVI) was significantly lower in PD during supine rest and recovery. Our results indicate for the first time that normal hemodynamics are disrupted during orthostatic stress and exercise in PD. Despite significant differences in EDVI at rest and during recovery, and SVRI during exercise, cardiac index was unaffected. Our finding of significantly blunted HRmax and HR recovery in PD patients has substantial implications for exercise prescription and recovery guidelines.

Effects of high-velocity circuit resistance and treadmill training on cardiometabolic risk, blood markers, and quality of life in older adults.

The presence of cardiometabolic syndrome (CMS) confers an increased risk for cardiovascular disease (CVD) and mortality and is associated with reduced health-related quality of life (HRQoL). Although the effects of exercise on biomarkers, HRQoL, and future risk have been studied, no study has measured the effects on all three components. The present study compared the effects of steady-state, moderate-intensity treadmill training (TM) and high-velocity circuit resistance training (HVCRT) on biological markers, HRQoL, and overall CVD risk in adults with CMS and CVD risk factors. Thirty participants (22 females, 8 males) were randomly assigned to 1 of 3 groups: HVCRT, TM, or control. Participants in the exercise groups attended training 3 days/week for a total of 12 weeks. Of the 30 participants who began the study, 24 (19 females, 5 males) were included in the final analysis. Primary outcome measures included CMS criteria, hemodynamic measures, Framingham Risk Score (FRS), and HRQoL. All variables were measured pre- and post-intervention. CMS z score significantly decreased for HVCRT (p = 0.03), while there were no significant changes for TM or control. FRS significantly decreased for HVCRT compared with TM (p = 0.03) and control (p = 0.03). Significant decreases in systolic (p < 0.01) and diastolic blood pressures (p < 0.01) for HVCRT accompanied significant increases from baseline in stroke volume (p = 0.03) and end-diastolic volume (p < 0.01). Systemic vascular resistance significantly decreased (p = 0.05) for HVCRT compared with control. Emotional well-being significantly improved following HVCRT and TM compared with control (p = 0.04; p = 0.03). HVCRT represents a novel training modality that improved factors in each of the 3 components assessed.

Loads and movement speed affect energy expenditure during circuit resistance exercise.

Circuit resistance training (CT) constitutes a high-intensity interval program commonly used to target weight loss; however, the loads and exercise patterns that maximize energy expenditure (EE) remain undetermined. We examined differences in EE among CT protocols using varying loads and contraction speeds in recreationally trained males and females. Seven males (age, 21.1 ± 0.5 years) and 8 females (age, 20.0 ± 0.9 years) performed 3 randomized CT protocols incorporating 3 circuits using heavy-load (80% 1-repetition maximum (1RM)) explosive (HLEC), heavy-load, controlled (2 s) (HLCC), and moderate-load (50% 1RM) explosive contractions (MLEC). Expired air was collected continuously before, during, and after exercise. Blood lactate was collected at rest, immediately postexercise, and 5 min postexercise. No significant differences were detected for resting EE; however, there was a significant difference among conditions during exercise (p = 0.034, ηp2 = 0.229). Post hoc analysis revealed that MLEC produced significantly higher EE than HLCC, but not HLEC (p = 0.023). There was a significant difference among conditions for rate of EE during exercise (p = 0.003, ηp2 = 0.361). Post hoc analysis revealed that HLEC produced a significantly higher EE rate than HLCC (p = 0.012) or MLEC (p = 0.001). A condition × sex interaction was seen for blood lactate changes (ηp2 = 0.249; p = 0.024). Females produced significantly greater change for MLEC than HLEC (p = 0.011), while males showed no significant differences. Our results favor CT using MLEC for a higher EE during a full workout; however, the rate of EE was highest when using HLEC.

Loads and Movement Speeds Dictate Differences in Power Output During Circuit Training.

Power training has become a common exercise intervention for improving muscle strength, power, and physical function while reducing injury risk. Few studies, however, have evaluated acute load changes on power output during traditional resistance training protocols. Therefore, the aim of this study was to quantify the effects of different loading patterns on power output during a single session of circuit resistance training (CRT). Nine male (age = 19.4 ± 0.9 years) and 11 female participants (age = 20.6 ± 1.6 years) completed 3 CRT protocols during separate testing sessions using 7 pneumatic exercises. Protocols included heavy load explosive contraction (HLEC: 80% one repetition maximum [1RM], maximum speed concentric-2 seconds eccentric), heavy load controlled contraction (HLCC: 80% 1RM, 2 seconds concentric-2 seconds eccentric), and moderate load explosive contraction (MLEC: 50% 1RM, maximum speed concentric-2 seconds eccentric). Protocols were assigned randomly using a counterbalanced design. Power for each repetition and set were determined using computerized software interfaced with each machine. Blood lactate was measured at rest and immediately postexercise. For male and female participants, average power was significantly greater during all exercises for HLEC and MLEC than HLCC. Average power was greatest during the HLEC for leg press (LP), hip adduction (ADD), and hip abduction (ABD) (p ≤ 0.05), whereas male participants alone produced their greatest power during HLEC for leg curl (LC) (p < 0.001). For male and female participants, significantly greater power was detected by set for LP, lat pull-down (LAT), ADD, LC, and ABD for the MLEC protocol (p < 0.02) and for LP, LAT, CP, and LC for the HLEC protocol (p < 0.03). A condition × sex interaction was seen for blood lactate changes ((Equation is included in full-text article.)= 0.249; p = 0.024), with female participants producing a significantly greater change for MLEC than HLEC (Mdiff = 1.61 ± 0.35 mmol·L; p = 0.011), whereas male participants showed no significant differences among conditions. Performing a CRT protocol using explosive training patterns, especially at high loads for lower-body exercises and moderate loads for upper-body exercises, produces significantly higher power than controlled speed training in most exercises. These results provide exercisers, personal trainers, and strength coaches with information that can assist in the design of training protocols to maximize power output during CRT.