Samuel Montalvo Hernandez

All Publications

• Effects of Different Stretching Modalities on the Antagonist and Agonist Muscles on Isokinetic Strength and Vertical Jump Performance in Young Men. Journal of strength and conditioning research Montalvo, S., Gonzalez, M. P., Dietze-Hermosa, M. S., Martinez, A., Rodriguez, S., Gomez, M., Cubillos, N., Ibarra-Mejia, G., Tan, E., Dorgo, S. 2024

  Abstract

  Montalvo, S, Gonzalez, MP, Dietze-Hermosa, MS, Martinez, A, Rodriguez, S, Gomez, M, Ibarra-Mejia, G, Tan, E, and Dorgo, S. Effects of different stretching modalities on the antagonist and agonist muscles on isokinetic strength and vertical jump performance in young men. J Strength Cond Res XX(X): 000-000, 2024-Exercise warm-up may include static or dynamic stretching, impacting performance differently. This study investigated the effects of various stretching protocols on isokinetic strength, muscular activity, and vertical jump performance. Sixteen subjects, divided evenly between trained and untrained groups, underwent 8 distinct stretching conditions in random order. Outcomes measured included isokinetic knee extension and flexion torque and power, muscular activity (vastus lateralis, vastus medialis, and biceps femoris), and jump performance (jump height and modified reactive strength index [RSImod]). Responses to the stretching conditions were analyzed using a mixed-methods approach. For isokinetic knee extension, dynamic stretching of both agonist and antagonist (DY-AG-ANT) and combined dynamic agonist with static antagonist stretching (DY-AG ST-ANT) produced significant improvements. Dynamic stretching of both agonist and antagonist increased peak torque by 12.72% and average torque by 30.80%, while DY-AG ST-ANT increased peak torque by 15.61% and average torque by 41.06%. Muscular activity also improved significantly; DY-AG ST-ANT increased EMG activity of the vastus lateralis by 29.43% and vastus medialis by 70.75%. Biceps femoris saw a 33.18% increase with DY-AG and a 22.15% increase with ST-AG. Countermovement jump height improved with DY-AG-ANT (12.6%) and static antagonist (ST-ANT) conditions (11.3%) ( p < 0.05). Dynamic stretching of both agonist and antagonist also enhanced average power knee extension by 32.41%, while ST-AG DY-ANT improved it by 31.09% ( p < 0.05). Dynamic stretching, especially when combined with static stretching, optimizes isokinetic strength, muscular activity, and jump height. Coaches should incorporate dynamic stretching, alone or with static antagonist stretching, to maximize performance.

  View details for DOI 10.1519/JSC.0000000000004937

  View details for PubMedID 39446677

• Exercise And Recovery Ventilatory Responses Between Individuals With Neuromuscular Disease And Healthy Adults Montalvo, S., Blumberg, Y., de Monts, C., Tang, W. J., Ataide, P., Young, S., Ghiollagain, N., Parker, D. M., Day, J. W., Myers, J. N., Wheeler, M. T., Duong, T., Christle, J. W. LIPPINCOTT WILLIAMS & WILKINS. 2024: 925-926

  View details for Web of Science ID 001315123204328

• Investigating Recovery From Maximal Exercise In Patients With Neuromuscular Disease Blumberg, Y., Patti, A., De Monts, C., Montalvo, S., Ataide, P., Tang, W., Young, S., Myers, J., Wheeler, M. T., Duong, T., Christle, J. W., Day, J. W. LIPPINCOTT WILLIAMS & WILKINS. 2024: 657

  View details for Web of Science ID 001315123203148

• Comparative kinematic analysis of high-speed treadmill vs. overground sprinting across athletic levels and sex. The Journal of sports medicine and physical fitness Montalvo, S., Gonzales, F., Lance, G., Gonzalez, M. P., Dietze-Hermosa, M. S., Dorgo, S. 2024

  Abstract

  This investigation aimed to dissect the kinematic differences in sprinting between high-speed treadmill and overground conditions, examining how these variations are influenced by the athlete's training status and biological sex.A total of 40 participants, 20 NCAA Division 1 sprinters and 20 recreational runners, performed a series of maximal sprints on a high-speed treadmill and on a standardized competition overground track. Sprinting kinematic variables such as stride length, stride frequency, contact time, and flight time were collected via photoelectric sensors. Maximal sprinting kinematics were analyzed by linear mixed-effects models, considering the impacts of sprinting environment (treadmill vs. overground), training level, and sex, with leg length as fixed factors and individual athletes as random effects. Statistical significance was set at a significance level of 0.05.The statistical analysis revealed that high-speed treadmill sprinting significantly affects all measured kinematic variables, leading to increased stride frequency and contact time. Elite sprinters demonstrated enhanced kinematic efficiency over recreational runners, characterized by increased stride length and frequency and reduced contact time. Sex-based kinematic distinctions also emerged, with male athletes exhibiting superior stride length and frequency compared to female athletes. Leg length significantly influenced stride frequency, and an interaction effect was observed for flight time between sprint type and athletic group.These findings elucidate the distinct biomechanical profiles across sprinting modalities and athlete demographics, emphasizing the need for sprint training customization. This study's insights offer a valuable reference for coaches and athletes to refine training and performance assessment in varied sprinting environments.

  View details for DOI 10.23736/S0022-4707.24.16089-6

  View details for PubMedID 39320031

• Effects of Different Eccentric Cycling Intensities on Brachial Artery Endothelial Shear Stress and Blood Flow Patterns. Research quarterly for exercise and sport Gomez, M., Montalvo, S., Sanchez, A., Conde, D., Ibarra-Mejia, G., Peñailillo, L. E., Gurovich, A. N. 2024: 1-11

  Abstract

  Eccentric exercise has gained attention as a novel exercise modality that increases muscle performance at a lower metabolic demand. However, vascular responses to eccentric cycling (ECC) are unknown, thus gaining knowledge regarding endothelial shear stress (ESS) during ECC may be crucial for its application in patients. The purpose of this study was to explore ECC-induced blood flow patterns and ESS across three different intensities in ECC. Eighteen young, apparently healthy subjects were recruited for two laboratory visits. Maximum oxygen consumption, power output, and blood lactate (BLa) threshold were measured to determine workload intensities. Blood flow patterns in the brachial artery were measured via ultrasound imaging and Doppler on an eccentric ergometer during a 5 min workload steady exercise test at low (BLa of 0-2 mmol/L), moderate (BLa 2-4 mmol/L), and high intensity (BLa levels > 4 mmol/L). There was a significant increase in the antegrade ESS in an intensity-dependent manner (baseline: 44.2 ± 8.97; low: 55.6 ± 15.2; moderate: 56.0 ± 10.5; high: 70.7 ± 14.9, all dynes/cm2, all p values < 0.0002) with the exception between low and moderate and Re (AU) showed turbulent flow at all intensities. Regarding retrograde flow, ESS also increased in an intensity-dependent manner (baseline 9.72 ± 4.38; low: 12.5 ± 3.93; moderate: 15.8 ± 5.45; high: 15.7 ± 6.55, all dynes/cm2, all p values < 0.015) with the exception between high and moderate and Re (AU) showed laminar flow in all intensities. ECC produced exercise-induced blood flow patterns that are intensity-dependent. This suggests that ECC could be beneficial as a modulator of endothelial homeostasis.

  View details for DOI 10.1080/02701367.2024.2404139

  View details for PubMedID 39302246

• Can the outlier percentiles from norms increase the sensitivity of the ECG criteria for screening athletes? Progress in cardiovascular diseases Tso, J. V., Montalvo, S., Christle, J., Froelicher, V. 2024

  View details for DOI 10.1016/j.pcad.2024.09.003

  View details for PubMedID 39278304

• Measuring Vertical Jump Height With Artificial Intelligence Through a Cell Phone: A Validity and Reliability Report. Journal of strength and conditioning research Erik, C. H., Weng Onn, S., Montalvo, S. 2024

  Abstract

  ABSTRACT: Erik, HT, Onn, SW, and Montalvo, S. Vertical jump height with artificial intelligence through a cell phone: a validity and reliability report. J Strength Cond Res XX(X): 000-000, 2024-This study estimated the reliability and validity of an artificial intelligence (AI)-driven model in the My Jump 2 (My Jump Lab) for estimating vertical jump height compared with the Force Platform (FP). The cross-sectional study involved 88 athletes (33 female and 55 male athletes), performing a total of 264 countermovement jumps with hands on hips. "Jump heights were simultaneously measured using the FP and the My Jump 2 app." The FP estimated jump heights using the impulse-momentum method, whereas My Jump 2 used the flight-time method, with the latter using an AI feature for automated detection of jump take-off and landing. Results indicated high reliability for the AI model (intraclass correlation coefficient [ICC1,3] = 0.980, coefficient of variation [CV] = 4.12) and FP (ICC1,3 = 0.990, CV = 2.92). Validity assessment showed strong agreement between the AI model and FP (ICC2,k = 0.973). This was also supported by the Bland-Altman analysis, and the ordinary least products regression revealed no significant systematic or proportional bias. The AI-driven model in My Jump 2 is highly reliable and valid for estimating jump height. Strength and conditioning professionals may use the AI-based mobile app for accurate jump height measurements, offering a practical and efficient alternative to traditional methods.

  View details for DOI 10.1519/JSC.0000000000004854

  View details for PubMedID 38953840

• Carotid Arterial Compliance during Different Intensities of Submaximal Endurance Exercise. Journal of clinical medicine Gurovich, A. N., Montalvo, S., Hassan, P. F., Gomez, M. 2024; 13 (11)

  Abstract

  Background: The purpose of this investigation was to determine the elastic characteristics of the common carotid artery (CCA) during endurance exercise at 3 different intensities. Methods: Twenty young healthy participants (10 males and 10 females) participated in this quasi-experimental cross-sectional study. Participants were tested in two sessions: (1) we took resting measurements of the elastic characteristics of the CCA and performed a cardiopulmonary exercise test (CPET) on a cycle ergometer to determine submaximal exercise intensities, and we conducted (2) measurements of the elastic characteristics of the CCA while exercising in a cycle ergometer at 3 intensities based on blood lactate levels of low (<2 mmol/L), moderate (2-4 mmol/L), and high (>4 mmol/L). Beta stiffness was calculated using CCA diameters during systole and diastole, measured with high-definition ultrasound imaging, and CCA systolic and diastolic pressures were measured via applanation tonometry. Results: Overall, there were no differences between males and females in terms of any of the studied variables (p > 0.05). In addition, no significant changes were found in the CCA beta stiffness and vessel diameter (p > 0.05) between exercise intensities. There was a significant exercise intensity effect on CCA systolic pressure (p < 0.05), but not on CCA diastolic pressure (p > 0.05). Conclusions: The biomechanical characteristics of the CCA, determined via compliance and beta-stiffness, do not change during cyclical aerobic exercise, regardless of exercise intensity.

  View details for DOI 10.3390/jcm13113316

  View details for PubMedID 38893027

  View details for PubMedCentralID PMC11173299

• The Impact of an 8-Week Resisted Sprint Training Program on Ice Skating Performance in Male Youth Ice Hockey Players. Journal of strength and conditioning research Dietze-Hermosa, M. S., Montalvo, S., Gonzalez, M. P., Dorgo, S. 2024

  Abstract

  Dietze-Hermosa, MS, Montalvo, S, Gonzalez, MP, and Dorgo, S. The impact of an 8-week, resisted, sprint training program on ice skating performance in male youth ice hockey players. J Strength Cond Res 38(5): 957-965, 2024-The purposes of this randomized control study were to (a) compare the effects of an on-ice versus an overground resisted sprint training intervention and a control condition and (b) identify changes in ice skating kinematics and kinetics after training intervention participation. Twenty-four youth ice hockey players were randomly allocated into 3 groups: (a) on-ice resisted sprint training (on-ice RST); (b) overground resisted sprint training (overground RST); and (c) body weight resistance training (control). During the 8-week intervention, the 2 RST groups engaged in sled towing methods, whereas the control group engaged in a body weight resistance training program twice a week. A series of individual, repeated-measures analysis of variances with post hoc pairwise comparisons were conducted for variables of interest. An interaction effect was noted for ice skating s-cornering agility drill completion time (p = 0.01; ηp2 = 0.36), ice skating 30-m top speed completion time (p = 0.04; ηp2 = 0.27), step length (p = 0.04; ηp2 = 0.26), and knee angle at touchdown (p = 0.03; ηp2 = 0.30). The on-ice RST group displayed superior improvements across ice skating tests compared with the control group. Data show that on-ice RST has the greatest transfer effect to ice skating metrics; however, improvements in certain ice skating metrics can be observed with overground training also.

  View details for DOI 10.1519/JSC.0000000000004732

  View details for PubMedID 38620058

• Digitized Electrocardiography Measurements Support the Biological Plausibility of the Pathological Significance of ST Segments in Athletes. Clinical journal of sport medicine : official journal of the Canadian Academy of Sport Medicine Montalvo, S., Froelicher, V. F., Hadley, D., Wheeler, M. T. 2024

  Abstract

  OBJECTIVE: ST segment deviations around the isoelectric line are common findings in manifest cardiovascular disease. In athletes, ST elevation is common, while ST depression is considered rare. However, clinical studies in athletes have associated ST depression with myocardial fibrosis and fatty infiltration and ST elevation with pericarditis and myocarditis. This study aims to explore the association between resting ST segment deviations and resting heart rate, an indicator of training and autonomic tone and electrocardiography (ECG) markers of exercise training effect and cardiovascular health R and T wave amplitude.DESIGN: Retrospective analysis of digitized ECG data.SETTING: Institutional setting.PARTICIPANTS: Seven thousand eight hundred thirty-six (male athletes = 4592, female athletes = 3244) healthy asymptomatic athletes (14-35 years).MAIN OUTCOME MEASURES: A series of correlations and regressions were conducted between ST depression (<0.0 V) and ST elevation (>0.0 V), on R and T wave amplitudes, and heart rate in leads V2, V5, and aVF.RESULTS: Positive correlations between ST elevation and R and T wave (S wave in V2) amplitudes and leads V5, V2, and aVF in male and female athletes (range of r = 0.1-0.54). In addition, there was a negative correlation between ST elevation and HR for male and female athletes. Finally, there was a negative correlation between ST depression and R wave and HR for male and female athletes in V5 (P < 0.01).CONCLUSIONS: In athletes, ST segment elevation is correlated with R and T wave amplitudes and negatively correlated with HR. In addition, ST segment elevation is correlated with low heart rate, consistent with its higher prevalence in athletes. ST segment depression is not influenced by HR but is negatively associated with R and T wave amplitudes.

  View details for DOI 10.1097/JSM.0000000000001199

  View details for PubMedID 38407231

• Should ECG criteria for Low QRS voltage (LQRSV) be specific for Sex? American heart journal Tso, J. V., Montalvo, S., Christle, J., Hadley, D., Froelicher, V. 2024

  Abstract

  Low QRS peak-to-nadir voltage (LQRSV) is associated with arrhythmogenic right ventricular cardiomyopathy (ARVC) and other cardiomyopathies. Recent studies have proposed criteria for LQRSV when screening athletes for cardiovascular disease. These criteria have not yet been evaluated in a large population of healthy young athletes.10,728 (42.5% female, 57.5% male, mean age 18.1±4.3 years) athletes who participated in mass ECG screenings between 2014-2021 at multiple sites across the United States including grade schools (11%), high schools (32%), colleges (50%), and professional athletic teams (6%) with digitally recorded ECGs and a standardized protocol were considered. Since by design, complete follow up for outcomes and the results of testing were not available. Including only ECGs from initial evaluation among athletes 14-35 years of age and excluding those with right bundle branch block, left bundle branch block, Wolf-Parkinson-White pattern, reversed leads and three clinically diagnosed cardiomyopathies at Stanford, 8,679 (58% males, 42% females) remained eligible for analysis. QRS voltage was analyzed for each ECG lead and LQRSV criteria were applied and stratified by sex.QRS voltage was lower in all leads in female athletes compared to male athletes. Using traditional limb lead criteria or precordial lead criteria, the prevalence of LQRSV was significantly lower in males than females (P<0.001). Strikingly, LQRSV using the Sokolow-Lyon Index was present in 1.9% of males and 9.8% of females (P<0.001). Applying 1st percentile for LQRS amplitude criteria provided possible values for screening young athletes for LQRSV.LQRSV is more common among female athletes than male athletes using established criteria. Using 1st percentile sex-specific cut points should be considered in future analyses. Proposed novel LQRSV criteria in young athletes should be specific for males and females.

  View details for DOI 10.1016/j.ahj.2024.02.002

  View details for PubMedID 38342392

• Assessing the Assisted Six-Minute Cycling Test as a Measure of Endurance in Non-Ambulatory Patients with Spinal Muscular Atrophy (SMA). Journal of clinical medicine Tang, W. J., Gu, B., Montalvo, S., Dunaway Young, S., Parker, D. M., de Monts, C., Ataide, P., Ni Ghiollagain, N., Wheeler, M. T., Tesi Rocha, C., Christle, J. W., He, Z., Day, J. W., Duong, T. 2023; 12 (24)

  Abstract

  Assessing endurance in non-ambulatory individuals with Spinal Muscular Atrophy (SMA) has been challenging due to limited evaluation tools. The Assisted 6-Minute Cycling Test (A6MCT) is an upper limb ergometer assessment used in other neurologic disorders to measure endurance. To study the performance of the A6MCT in the non-ambulatory SMA population, prospective data was collected on 38 individuals with SMA (13 sitters; 25 non-sitters), aged 5 to 74 years (mean = 30.3; SD = 14.1). The clinical measures used were A6MCT, Revised Upper Limb Module (RULM), Adapted Test of Neuromuscular Disorders (ATEND), and Egen Klassifikation Scale 2 (EK2). Perceived fatigue was assessed using the Fatigue Severity Scale (FSS), and effort was assessed using the Rate of Perceived Exertion (RPE). Data were analyzed for: (1) Feasibility, (2) Clinical discrimination, and (3) Associations between A6MCT with clinical characteristics and outcomes. Results showed the A6MCT was feasible for 95% of the tested subjects, discriminated between functional groups (p = 0.0086), and was significantly associated with results obtained from RULM, ATEND, EK2, and Brooke (p < 0.0001; p = 0.029; p < 0.001; p = 0.005). These findings indicate the A6MCT's potential to evaluate muscular endurance in non-ambulatory SMA individuals, complementing clinician-rated assessments. Nevertheless, further validation with a larger dataset is needed for broader application.

  View details for DOI 10.3390/jcm12247582

  View details for PubMedID 38137651

  View details for PubMedCentralID PMC10743820

• Effects of manual resistance versus weight resistance training on body composition and strength in young adults after a 14-week intervention. Journal of bodywork and movement therapies Dorgo, S., Terrazas, L. A., Gonzalez, M. P., Dietze-Hermosa, M. S., Montalvo, S. 2023; 36: 313-319

  Abstract

  Manual Resistance Training (MRT) is an alternative training modality where the external resistance is provided by a spotter.The purpose of this study was to observe changes in body composition and muscular fitness after a 14-week MRT intervention compared to changes elicited by a Weight Resistance Training (WRT) intervention.Eighty-four young adults were randomly assigned to either the MRT (n = 53, height 170.1 ± 8.1 cm, body mass 73.9 ± 16.0 kg, and body fat 24.6 ± 8.7%) or WRT (n = 31, mean ± SD: height 169.6 ± 10.1 cm, body mass 75.0 ± 17.4 kg, and body fat 24.7 ± 8.5%) group. Body composition was assessed by Dual-energy X-ray Absorptiometry (DEXA), muscular strength and muscular endurance were tested before and after the intervention.Findings indicated that trunk, arm, leg, and total lean mass increased in both groups after the intervention (p < 0.05). Moreover, total fat mass significantly decreased compared to baseline in both groups (p < 0.05). However, no statistically significant changes were observed in Bone Mineral Density and Bone Mineral Content in response to the intervention. Both MRT and WRT programs were successful at significantly increasing muscular strength and endurance (p < 0.05).The changes in body composition after a 14-week MRT program were similar to those of the WRT intervention. Hence, an MRT program may be effectively used to increase lean mass and decrease fat mass.

  View details for DOI 10.1016/j.jbmt.2023.06.013

  View details for PubMedID 37949578

• ST Segment Depression In Male Athletes Montalvo, S., Froelicher, V. F., Myers, J. N., Wheeler, M. T. LIPPINCOTT WILLIAMS & WILKINS. 2023: 202-203

  View details for Web of Science ID 001158156600456

• Biomechanical Characteristics Of The Carotid Artery During Aerobic Exercise Gomez, M., Montalvo, S., Sanchez, A., Hassan, P., Gurovich, A. N. LIPPINCOTT WILLIAMS & WILKINS. 2023: 48

  View details for Web of Science ID 001158156600109

• Commercial Smart Watches and Heart Rate Monitors: A Concurrent Validity Analysis. Journal of strength and conditioning research Montalvo, S., Martinez, A., Arias, S., Lozano, A., Gonzalez, M. P., Dietze-Hermosa, M. S., Boyea, B. L., Dorgo, S. 2023

  Abstract

  Montalvo, S, Martinez, A, Arias, S, Lozano, A, Gonzalez, MP, Dietze-Hermosa, MS, Boyea, BL, and Dorgo, S. Smartwatches and commercial heart rate monitors: a concurrent validity analysis. J Strength Cond Res XX(X): 000-000, 2022-The purpose of this study was to explore the concurrent validity of 2 commercial smartwatches (Apple Watch Series 6 and 7) against a clinical criterion device (12-lead electrocardiogram [ECG]) and a field criterion device (Polar H-10) during exercise. Twenty-four male collegiate football players and 20 recreationally active young adults (10 men and 10 women) were recruited and participated in a treadmill-based exercise session. The testing protocol included 3 minutes of standing still (resting), then walking at low intensity, jogging at a moderate intensity, running at a high intensity, and postexercise recovery. The intraclass correlation (ICC2,k), and Bland-Altman plot analyses showed a good validity of the Apple Watch Series 6 and Series 7 with increased error (bias) as jogging and running speed increased in the football and recreational athletes. The Apple Watch Series 6 and 7 are highly valid smartwatches at rest and different exercise intensities, with validity decreasing with increased running speed. Strength and conditioning professionals and athletes can confidently use the Apple Watch Series 6 and 7 when tracking heart rate; however, caution must be taken when running at moderate or higher speeds. The Polar H-10 can surrogate a clinical ECG for practical applications.

  View details for DOI 10.1519/JSC.0000000000004482

  View details for PubMedID 36862131

• Differences in sprint profile, sprint completion times, and jumping performance between division I track and field sprinters Journal of Physical Education and Sport Dietze-Hermosa, M., Montalvo, S., Gonzales, M. P., Cubillos, N. R., Dorgo, S. 2023; 20: 2076-2085

  View details for DOI 10.7752/jpes.2020.s3280

• Dynamic stretching improves muscle activation and pain pressure threshold but not isometric hand strength when compared to static stretching Journal of Physical Education and Sport Montalvo, S., Conde, D., Sanchez, M., Martinez, P., Trevizo, R., Ibarra-Mejia, G. 2023; 2 (23): 293 - 300

  View details for DOI 10.7752/jpes.2023.02035

• A Comparison of Morphological, Jump, and Sprint Kinematic Asymmetries in Division I Track and Field Athletes. International journal of exercise science Gonzalez, M. P., Montalvo, S., Dietze-Hermosa, M., Gomez, M., Dorgo, S. 2023; 16 (1): 1306-1319

  Abstract

  Inter-limb asymmetries are the difference in performance in one limb with respect to the other. Running events in track and field are considered symmetrical while jumping and throwing events are considered asymmetrical. It is unknown if competing in these different events result in differences in inter-limb asymmetries, thus, this study compared the magnitude of jump, sprint, and morphological asymmetries in track and field athletes who compete in symmetrical and asymmetrical events. Forty-six Division I track and field athletes performed a series of vertical jumps (VJ) and broad jumps (BJ) with force platforms measuring peak force of each limb, and 30-meter fly sprints with kinematics (step length (SL), flight time (FT), and contact time (CT)) recorded during the sprints. Additionally, thirty-eight of these subjects underwent body composition analysis via dual x-ray absorptiometry to determine morphological asymmetries. Asymmetries were calculated using the symmetry index and the asymmetry measures were compared between sprinters, distance runners, throwers, and jumpers utilizing a one-way analysis of variance or Kruskal-Wallis tests with post-hoc comparisons as necessary. There were no differences in VJ, BJ, and sprint kinematic asymmetries found between groups but there were differences in leg fat mass asymmetries (H(3)=8.259, p=0.041, eta2= 0.101) as well as arm lean mass (H(3)=9.404, p=0.024, eta2=0.152), fat mass (H(3)=17.822, p<0.001, eta2=0.353), and tissue mass (H(3)=11.632, p=0.009, eta2=0.206) asymmetry measures. While morphological asymmetry differences may be present in athletes competing in different events, there does not appear to be differences in asymmetries during the VJ, BJ, and 30-m fly sprint.

  View details for PubMedID 38288257

• Near Infrared Spectroscopy is not a Surrogate of Venous Occlusion Plethysmography to Assess Microvascular Resting Blood Flow and Function. International journal of exercise science Gomez, M., Montalvo, S., Gurovich, A. N. 2022; 15 (2): 1616-1626

  Abstract

  Near-infrared spectroscopy (NIRS) is a non-invasive technique that measures tissue perfusion using red blood cells oxygen saturation and venous occlusion plethysmography (VOP) is the gold standard to assess microvascular blood flow and function. The purpose of this study was to determine if NIRS can surrogate the microvascular blood flow assessment after an ischemic challenge obtained via VOP. Twenty apparently healthy subjects (10 males and 10 females), aged 18 to 35 years, were recruited for this single session study. NIRS probes were placed 40mm apart along the epicondylar muscles on the right forearm and on the tibialis anterior on the right lower leg, while VOP strain gauges were placed on the largest circumference on both right forearm and calf. Blood flow via VOP and NIRS variables (hemoglobin saturation (SO2), oxygenated hemoglobin (HbO2), and deoxyhemoglobin (HHb) slopes) were assessed before and after 5-min ischemic challenge. Person's correlations and intra-class correlations (ICC2k) were conducted for each of the NIRS variables vs VOP. There were moderate associations between of SO2 and HbO2 slopes and VOP (r = 0.59, p < 0.01 and r = 0.53, p < 0.05, respectively) at the lower body during resting conditions. There was a poor agreement between NIRS SO2 and VOP at the resting condition in the lower body (ICC2k = 0.45). There were no other associations between any of the other NIRS variables and VOP of the lower and upper body at resting or post-ischemic conditions. In conclusion, NIRS cannot surrogate VOP for measurements of microvascular blood flow at resting or post-ischemic conditions.

  View details for PubMedID 36582307

  View details for PubMedCentralID PMC9762160

• Differences in Blood Flow Patterns and Endothelial Shear Stress at the Carotid Artery Using Different Exercise Modalities and Intensities FRONTIERS IN PHYSIOLOGY Montalvo, S., Gomez, M., Lozano, A., Arias, S., Rodriguez, L., Morales-Acuna, F., Gurovich, A. N. 2022; 13: 857816

  Abstract

  Endothelial dysfunction is the first pathophysiological step of atherosclerosis, which is responsible for 90% of strokes. Exercise programs aim to reduce the risk of developing stroke; however, the majority of the beneficial factors of exercise are still unknown. Endothelial shear stress (ESS) is associated with endothelial homeostasis. Unfortunately, ESS has not been characterized during different exercise modalities and intensities in the carotid artery. Therefore, the purpose of this study was to determine exercise-induced blood flow patterns in the carotid artery. Fourteen apparently healthy young adults (males = 7, females = 7) were recruited for this repeated measures study design. Participants completed maximal oxygen consumption (VO2max) tests on a Treadmill, Cycle-ergometer, and Arm-ergometer, and 1-repetition maximum (1RM) tests of the Squat, Bench Press (Bench), and Biceps Curl (Biceps) on separate days. Thereafter, participants performed each exercise at 3 different exercise intensities (low, moderate, high) while a real-time ultrasound image and blood flow of the carotid artery was obtained. Blood flow patterns were assessed by estimating ESS via Womersley's estimation and turbulence via Reynold's number (Re). Data were analyzed using a linear mixed-effects model. Pairwise comparisons with Holm-Bonferroni correction were conducted with Hedge's g effect size to determine the magnitude of the difference. There was a main effect of intensity, exercise modality, and intensity * exercise modality interaction on both ESS (p < 0.001). Treadmill at a high intensity yielded the greatest ESS when compared to the other exercise modalities and intensities, while Bench Press and Biceps curls yielded the least ESS. All exercise intensities across all modalities resulted in turbulent blood flow. Clinicians must take into consideration how different exercise modalities and intensities affect ESS and Re of the carotid artery.

  View details for DOI 10.3389/fphys.2022.857816

  View details for Web of Science ID 000799590100001

  View details for PubMedID 35620608

  View details for PubMedCentralID PMC9127153

• Changes in vertical jump performance and body composition before and after COVID-19 lockdown Journal of Human Exercise and Sport Tan, E., Montalvo, S., Gonzales, M. P., Dietze-Hermosa, M. S., MIN, S., Dorgo, S. 2022; 18 (1): 224-241

  View details for DOI 10.14198/jhse.2023.181.18

• Association and Predictive Ability of Jump Performance with Sprint Profile of Collegiate Track and Field Athletes SPORTS BIOMECHANICS Dietze-Hermosa, M., Montalvo, S., Gonzalez, M. P., Rodriguez, S., Cubillos, N. R., Dorgo, S. 2021: 1-20

  Abstract

  This study examined the relationship between broad jump (BJ), countermovement jump (CMJ) and light load countermovement jump (LL-CMJ) performance and sprint performance and Sprint Profile measures in athletes. Additionally, this study aimed to determine the predictive ability of jump measures on Sprint Profile components. Twenty-five athletes performed BJ, CMJ, LL-CMJ, 30-metre acceleration and 30-metre maximal speed fly-by sprints. Results revealed moderate to very large correlations between BJ, CMJ and LL-CMJ performance with acceleration sprint completion times (r = -0.423 to -0.807; p < 0.05), fly-by sprint completion times (r = -0.452 to -0.838; p < 0.05) and maximal sprint speed (r = 0.424 to 0.794; p < 0.05). Additionally, associations were observed with multiple jumping measures and components of the Sprint Profile (r = 0.431 to 0.777; p < 0.05) during acceleration sprints. Furthermore, the BJ distance was the best predictor of Sprint Profile components during acceleration sprints (R2 = 0.57-0.76; p < 0.01) and maximal speed fly-by sprints (R2 = 0.775; p < 0.001). The forces and the manner of force application during the BJ to propel the athlete forwards and upwards are similar to those necessary to exhibit superior sprint performance. This may be due to the rapid generation of forces and orientation of force application during both movements.

  View details for DOI 10.1080/14763141.2021.2000022

  View details for Web of Science ID 000722553000001

  View details for PubMedID 34818989

• Effects of Augmented Eccentric Load Bench Press Training on One Repetition Maximum Performance and Electromyographic Activity in Trained Powerlifters JOURNAL OF STRENGTH AND CONDITIONING RESEARCH Montalvo, S., Gruber, L. D., Gonzalez, M. P., Dietze-Hermosa, M. S., Dorgo, S. 2021; 35 (6): 1512-1519

  Abstract

  Montalvo, S, Gruber, LD, Gonzalez, MP, Dietze-Hermosa, MS, and Dorgo, S. Effects of augmented eccentric load bench press training on one repetition maximum performance and electromyographic activity in trained powerlifters. J Strength Cond Res 35(6): 1512-1519, 2021-Augmented eccentric load (AEL) training has been shown to elicit greater lower-body muscular strength increases and faster performance improvements compared with traditional strength training. However, it is unknown whether AEL training could provide similar improvements in upper-body muscular strength. Therefore, this study investigated the effects of a 4-week AEL training program on bench press one repetition maximum (1RM) strength, bar kinetics and kinematics, and surface electromyography (EMG) activity. Eight competitive powerlifters completed 5 training sessions consisting of 7 sets of a single repetition with up to 5 minutes rest between sets. Each session was completed at a predetermined AEL percentage consisting of 90% 1RM for concentric and supramaximal loads ranging from 105 to 125% 1RM during the eccentric phase with the use of eccentric hooks. After 4 weeks of AEL training, 1RM performance significantly increased from pretest to posttest (116.62 ± 27.48-124.28 ± 26.96 kg, p = 0.001). In addition, EMG amplitude of the pectoralis major decreased during the 125% AEL session to 59.86 ± 15.36% of pretest 1RM EMG values (p = 0.049, effect sizes [ESs] = 0.69). Furthermore, peak power of 1RM increased by 36.67% from pretest to posttest (p = 0.036, ES = 0.58). These study findings suggest that incorporating AEL bench press training into a 4-week training cycle may be a novel strategy to improve 1RM performance in competitive powerlifters in a short period.

  View details for DOI 10.1519/JSC.0000000000004030

  View details for Web of Science ID 000711779600005

  View details for PubMedID 34027918

• Common Vertical Jump and Reactive Strength Index Measuring Devices: A Validity and Reliability Analysis JOURNAL OF STRENGTH AND CONDITIONING RESEARCH Montalvo, S., Gonzalez, M. P., Dietze-Hermosa, M. S., Eggleston, J. D., Dorgo, S. 2021; 35 (5): 1234-1243

  Abstract

  Montalvo, S, Gonzalez, MP, Dietze-Hermosa, M, Eggleston, JD, and Dorgo, S. Common vertical jump and reactive strength index measuring devices: A validity and reliability analysis. J Strength Cond Res 35(5): 1234-1243, 2021-Several field-test devices exist to assess vertical jump, but they either lack proper validation or have been validated for the countermovement jump (CMJ) only. This study aimed to quantify the validity and reliability of metrics, including jump height and the calculated reactive strength index (RSI), obtained using the flight-time method from 4 different assessment devices with 3 different vertical jump modalities in comparison to a force platform (criterion assessment). The Optojump, Push-Band 2.0, MyJump2 mobile application, and What'sMyVert mobile application were used synchronously and together with the force platforms. Thirty subjects (17 males and 13 females; age ± SD: 23.37 ± 1.87 years) performed 5 repetitions of CMJ, squat jump (SQJ), and drop jump (DJ) with a standardized 90° knee flexion for all jumps. Relative reliability was determined by intraclass correlation (ICC) and absolute reliability by coefficient of variation (CV) analyses. Excellent reliability was considered as ICC > 0.9 and CV < 10%. Validity was obtained through an ordinary least products regression, ICC, and CV. Significance was set at p < 0.05. Reliability was excellent on jump height for the CMJ (ICC ≥ 0.98; CV ≤ 8.14%) for all instruments. With the exception of the Optojump, all instruments also had excellent reliability for the SQJ (ICC ≥ 0.98; CV ≤ 6.62) and DJ (ICC ≥ 0.94; CV ≤ 8.19). For the RSI metric, all instruments had excellent relative reliability (ICC ≥ 0.92), but none had excellent absolute reliability (CV ≥ 12.5%). The MyJump2 and What'sMyVert apps showed excellent validity on all jump modalities and RSI. The Optojump and Push-Band 2.0 devices both showed system and proportional bias for several jump modalities and RSI. Overall, both mobile applications may provide coaches with a cost-effective and reliable measurement of various vertical jumps.

  View details for DOI 10.1519/JSC.0000000000003988

  View details for Web of Science ID 000658820300011

  View details for PubMedID 33629975

• Association Between the Modified Functional Movement Screen Scores, Fear of Falling, and Self-Perceived Balance in Active Older Adults TOPICS IN GERIATRIC REHABILITATION Dietze-Hermosa, M. S., Montalvo, S., Gonzalez, M. P., Dorgo, S. 2021; 37 (2): 64-73

  View details for DOI 10.1097/TGR.0000000000000306

  View details for Web of Science ID 000657421700003

• Physical fitness in older adults: Is there a relationship with the modified Functional Movement Screen (TM)? JOURNAL OF BODYWORK AND MOVEMENT THERAPIES Dietze-Hermosa, M., Montalvo, S., Gonzalez, M. P., Dorgo, S. 2021; 25: 28-34

  Abstract

  The modified Functional Movement Screen™ (mFMS) has been used to screen for mobility, stability, motor control, and balance in older adults, yet, its relationship to measures of physical fitness is not fully understood. The purpose of this study was to determine the association between mFMS scores and measures of physical fitness in older adults. A secondary aim was to determine physical fitness differences depending on mFMS Lower Body Motor Control Screen scores.One hundred and eight older adults completed this cross-sectional study. Measurements of physical fitness included: Handgrip Strength (HG), Back-Leg Strength Dynamometer (BLS), 8 foot Up and Go (8UG), Vertical Jump (VJ), Medicine Ball Throw (MBT), Chair Stand (CST), Arm Curl (AC), and 6-Minute Walk test (6 MW). The mFMS consisted of four screens: Shoulder Mobility Screen (SMS), Deep Squat (DS), Active Straight Leg Raise (ASLR), and a Lower Body Motor Control Screen (LB-MCS). Spearman's R correlations determined associations between physical fitness tests and mFMS scores (DS, SMS, ASLR). Independent t-tests or Mann Whitney U tests determined whether individuals who passed the LB-MCS displayed higher physical fitness scores.The DS was significantly correlated with all fitness measures (p < 0.05). Higher DS scores were associated with better HG (r = 0.31), BLS (r = 0.49), VJ height (r = 0.54), MBT (r = 0.41), CST (r = 0.57), AC (r = 0.30), 6 MW (r = 0.50), and 8UG (r = -0.61) performance. Individuals who passed the LB-MCS displayed superior BLS, 8UG test, and 6 MW test performance (p < 0.05).Higher DS scores are associated with higher physical fitness scores. Individuals who passed the LB-MCS displayed better physical fitness scores. Practitioners may desire to use the mFMS to measure physical fitness in older adults.

  View details for DOI 10.1016/j.jbmt.2020.11.019

  View details for Web of Science ID 000631984400005

  View details for PubMedID 33714507

• Heart rate percentage as a method for determining intra-set resting during a post-activation performance enhancement exercise to increase vertical jump performance Journal of Physical Education and Sport Montalvo, S., Conde, D., Gonzales, M. P., Dietze-Hermosa, M. S., Ibarra-Mejia, G., Dorgo, S. 2021; 21 (5): 730 – 2736

  View details for DOI 10.7752/jpes.2021.05363

• Sprint Training on a Treadmill vs. Overground Results in Modality-Specific Impact on Sprint Performance but Similar Positive Improvement in Body Composition in Young Adults JOURNAL OF STRENGTH AND CONDITIONING RESEARCH Dorgo, S., Perales, J. J., Boyle, J. B., Hausselle, J., Montalvo, S. 2020; 34 (2): 463-472

  Abstract

  Dorgo, S, Perales, JJ, Boyle, JB, Hausselle, J, and Montalvo, S. Sprint training on a treadmill vs. overground results in modality-specific impact on sprint performance but similar positive improvement in body composition in young adults. J Strength Cond Res XX(X): 000-000, 2018-The effects of different sprint training modalities on body composition are not yet known, and the effectiveness of using motorized treadmills for sprint training is yet to be assessed accurately. The following study investigated the effects of motorized treadmill and overground training on sprint performance and body composition. Sixty-four young adults (33 men and 31 women) completed 12 sprint training sessions over a 6-week period either on a treadmill (TM) or overground (TR), or followed their normal exercise routine (CONTROL). Fifty-yard sprint time, 20-yard maximal sprint speed split time, and maximal treadmill speed were used as sprint performance indicators. Body composition and sprint performance assessments were completed before and after the 6-week intervention. On completion of the 6-week training program, maximal treadmill speed significantly increased for all 3 groups, while split sprint time significantly decreased for the TR group. The CONTROL group's 50-yd sprint time and split sprint time significantly worsened after 6 weeks. Improvements in sprint time and speed were significantly greater for the TR and TM groups compared with the CONTROL group for 50-yd sprint time, 20-yard maximal sprint speed split time, and maximal treadmill sprint speed. The change in maximal treadmill sprint speed for the TM group was significantly greater than that of the TR group. TR and TM subjects also showed significant decrease in total body fat and increase in leg lean muscle mass. These findings indicate that although overground sprint training resulted in the greatest performance improvements within overground sprint tests, sprint training on a motorized treadmill may be a beneficial alternative modality to overground sprint training and may also positively impact subjects' body composition.

  View details for DOI 10.1519/JSC.0000000000003024

  View details for Web of Science ID 000524362300022

  View details for PubMedID 30741862

• Association and predictive ability of vertical countermovement jump performance on unilateral agility in recreationally trained individuals Journal of Physical Education and Sport Dietze-Hermosa, M., Montalvo, S., Cubillo, N. R., Gonzales, M. P., Dorgo, S. 2020; 20: 2076-2085

  View details for DOI 10.7752/jpes.2020.s3280

• The effect of different stretching protocols on vertical jump measures in college age gymnasts JOURNAL OF SPORTS MEDICINE AND PHYSICAL FITNESS Montalvo, S., Dorgo, S. 2019; 59 (12): 1956-1962

  Abstract

  Gymnastics is a sport that requires rapid display of explosive power expressed through the vertical jump. Recent studies have shown that a static-stretching based warm-up is ineffective for explosive power development. The aim of this study was to compare different stretching protocols and their effect on vertical jump measures.Eleven gymnasts (9 males, 2 females; 23.18±2.52 yrs) participated in this randomized crossover study. Participants were measured on the countermovement jump (CMJ), squat jump (SQJ), and depth jump (DJ) at baseline (no warm-up). Participants were then randomly placed into one of four stretching protocols: Static (ST), dynamic (DY), static + dynamic (ST+DY), and dynamic + static (DY+ST) and tested on the CMJ, SQJ, and DJ. A photoelectric cell device was used to measure vertical jump height (VJH), flight time (FT), power output (PO), and Reactive Strength Index (RSI). The non-parametric Friedman test was used to test differences between stretching protocols.The DY protocol showed significant improvements in VJH, FT, and PO in the CMJ. The ST, ST+DY, and DY+ST protocols did not show any significant improvements.A warm-up consisting of dynamic movements that resemble those used in the sport of gymnastics can improve vertical jump measures, as reflected through the CMJ.

  View details for DOI 10.23736/S0022-4707.19.09561-6

  View details for Web of Science ID 000507479700004

  View details for PubMedID 31933341

• Validity of Vertical Jump Measuring Devices International Journal of Exercise Science: Conference Proceedings Montalvo, S., Dorgo, S., Tune, C. H., Sapien, A. C., Gonzalez, M. P., Sanchez, J. A. 2018
• The Effects of Overground and Treadmill Sprint Training on Body Composition National Strength and Conditioning Association Conference Proceedings Dorgo, S., Perales, J., Montalvo, S. 2018
• The Effects of Two Different Sprint Training Modalities on Sprint Speed, Aerobic Fitness and Body Composition International Journal of Exercise Science: Conference Proceedings Amador, M., Montalvo, S., Perales, J., Dorgo, S., Bajpeyi, S. 2016
• Effects of Treadmill and Overground Sprint Training Modes on Sprint Speed, Body Composition and Aerobic Power National Strength and Conditioning Conference Association Proceeding Dorgo, S., Perales, J., Montalvo, S., Amador, M., Bajpeyi, B. 2016