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Ottinger CR, Tufano JJ, Cochrane-Snyman KC, Gheith RH, McBride JM. Offset Loading in a Bilateral Squatting Movement Pattern Influences Ground-Reaction Force and Muscle Activity in the Dominant and Nondominant Limb. Int J Sports Physiol Perform 2023; 18:523-529. [PMID: 36944365 DOI: 10.1123/ijspp.2022-0407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 01/18/2023] [Accepted: 01/25/2023] [Indexed: 03/23/2023]
Abstract
PURPOSE The purpose of this study was to explore whether offset loading in the barbell squat altered ground-reaction force (GRF) and muscle activation in the dominant (D) and nondominant (ND) lower limb compared to traditional squats. METHODS Twelve well-trained men (age 26.4 [3.2] y; 10.3 [1.9] y experience) performed 3 sets of 10 repetitions at 60% of their previously measured 1-repetition maximum. Sets were quasi-randomized between traditional loading (TDL), dominant-side offset loading (OS-D), and nondominant-side offset loading (OS-ND). All repetitions were performed on a dual force plate with electromyography sensors on the prime mover muscles of the squat. GRF symmetry was assessed using the symmetry index (SI) to determine the direction (D [+] or ND [-]) and magnitude (%) of the asymmetry. Finally, the first 3 and final 3 repetitions of each set were compared for compensatory changes in symmetry. RESULTS OS-D induced a significant change in limb SI relative to TDL (5.21% vs 1.44%; P = .011); however, no significant difference in limb SI was seen between TDL and OS-ND (-0.66% vs 1.44%; P = .278). No asymmetries between D and ND muscle activation were present in any condition. TDL and OS-D squats exhibited significant improvements in limb SI between the first 3 and final 3 repetitions (P = .035 and .011, respectively); however, no such improvement was seen in OS-ND. CONCLUSIONS OS-D is capable of significantly altering GRF limb SI in a bilateral squat; however, OS-ND appears to exhibit no GRF or electromyography effects relative to TDL. Thus, the results of this study do not support the use of OS-ND in the pursuit of strengthening a weaker limb, suggesting that unilateral training may be a preferred mode of exercise for this desired outcome.
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Affiliation(s)
- Charlie R Ottinger
- Applied Science and Performance Institute, Tampa, FL,USA
- Concordia University Chicago, River Forest, IL,USA
| | - James J Tufano
- Concordia University Chicago, River Forest, IL,USA
- Charles University, Prague,Czech Republic
| | | | - Raad H Gheith
- Applied Science and Performance Institute, Tampa, FL,USA
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Kerns JA, Zwart AS, Perez PS, Gurchiek RD, McBride JM. Effect of IMU location on estimation of vertical ground reaction force during jumping. Front Bioeng Biotechnol 2023; 11:1112866. [PMID: 37020514 PMCID: PMC10067619 DOI: 10.3389/fbioe.2023.1112866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 03/10/2023] [Indexed: 04/07/2023] Open
Abstract
Introduction: Several investigations have examined utilizing inertial measurement units (IMU) to estimate ground reaction force (GRF) during exercise. The purpose of this investigation was to determine the effect of inertial measurement units location on the estimation of ground reaction force during vertical jumping. Methods: Eight male subjects completed a series of ten countermovement jumps on a force plate (FP). The subjects had an inertial measurement units attached to the sacrum, back and chest. Ground reaction force was estimated from data from the individual inertial measurement units and by using a two-segment model and combined sensor approach. Results: The peak ground reaction force values for the sacrum, back, chest and combined inertial measurement units were 1,792 ± 278 N, 1,850 ± 341 N, 2,054 ± 346 N and 1,812 ± 323 N, respectively. The sacral inertial measurement units achieved the smallest differences for ground reaction force estimates providing a root mean square error (RMSE) between 88 N and 360 N. The inertial measurement units on the sacrum also showed significant correlations in peak ground reaction force (p < 0.001) and average ground reaction force (p < 0.001) using the Bland-Altman 95% Limits of Agreement (LOA) when in comparison to the force plate. Discussion: Based on assessment of bias, Limits of Agreement, and RMSE, the inertial measurement units located on the sacrum appears to be the best placement to estimate both peak and average ground reaction force during jumping.
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Stewart JA, Merritt EK, Lidstone DE, McBride JM, Zwetsloot KA. Prolonged cycling lowers subsequent running mechanical efficiency in collegiate triathletes. BMC Sports Sci Med Rehabil 2022; 14:149. [PMID: 35915467 PMCID: PMC9344700 DOI: 10.1186/s13102-022-00543-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 07/22/2022] [Indexed: 11/24/2022]
Abstract
Background A significant challenge that non-elite collegiate triathletes encounter during competition is the decline in running performance immediately after cycling. Therefore, the purpose of this study was to determine if performing a 40-km bout of cycling immediately before running would negatively influence running economy and mechanical efficiency of running during simulated race conditions in collegiate triathletes. Methods Eight competitive club-level collegiate triathletes randomly performed two trials: cycling for 40 km (Cycle-Run) or running for 5 km (Run–Run), immediately followed by a four-minute running economy and mechanical efficiency of running test at race pace on an instrumented treadmill. Blood lactate, respiratory exchange ratio, mechanical work, energy expenditure, and muscle glycogen were also measured during the four-minute running test. Results Mechanical efficiency of running, but not running economy, was significantly lower in Cycle-Run, compared to Run–Run (42.1 ± 2.5% vs. 48.1 ± 2.5%, respectively; p = 0.027). Anaerobic energy expenditure was significantly higher in the Cycle-Run trial, compared to the Run–Run trial (16.3 ± 2.4 vs. 7.6 ± 1.1 kJ; p = 0.004); while net (151.0 ± 12.3 vs. 136.6 ± 9.6 kJ; p = 0.204) and aerobic energy expenditure (134.7 ± 12.3 vs. 129.1 ± 10.5 kJ; p = 0.549) were not statistically different between trials. Analysis of blood lactate, respiratory exchange ratio, mechanical work, and changes in muscle glycogen revealed no statistically significant differences between trials. Conclusions These results suggest that mechanical efficiency of running, but not running economy, is decreased and anaerobic energy expenditure is increased when a 40-km bout of cycling is performed immediately before running in collegiate triathletes.
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Affiliation(s)
- J A Stewart
- Integrative Muscle Physiology Laboratory, Appalachian State University, ASU Box 32071, Boone, NC, USA.,Biomechanics and Neuromuscular Laboratory, Appalachian State University, ASU Box 32071, Boone, NC, USA
| | - E K Merritt
- Kinesiology Department, Southwestern University, 1001 E. University Ave., Georgetown, TX, USA
| | - D E Lidstone
- Biomechanics and Neuromuscular Laboratory, Appalachian State University, ASU Box 32071, Boone, NC, USA
| | - J M McBride
- Biomechanics and Neuromuscular Laboratory, Appalachian State University, ASU Box 32071, Boone, NC, USA.,Department of Health and Exercise Science, Appalachian State University, ASU Box 32071, Boone, NC, 28608, USA
| | - K A Zwetsloot
- Integrative Muscle Physiology Laboratory, Appalachian State University, ASU Box 32071, Boone, NC, USA. .,Department of Health and Exercise Science, Appalachian State University, ASU Box 32071, Boone, NC, 28608, USA.
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McBride JM, Hackmann MJ, Nimphius S, Cense B. Erratum: In vivo PS-OCT needle probe scan of human skeletal muscle: publisher's note. Biomed Opt Express 2022; 13:2682. [PMID: 35774320 PMCID: PMC9203091 DOI: 10.1364/boe.460320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Indexed: 06/15/2023]
Abstract
[This corrects the article on p. 1386 in vol. 13, PMID: 35414965.].
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Affiliation(s)
- Jeffrey M. McBride
- Department of Health and Exercise Science, Appalachian State University, Boone, NC 28608, USA
- School of Medical and Health Sciences, Edith Cowan University, Joondalup, 6027, Australia
- Contributed equally
| | - Michael J. Hackmann
- School of Human Sciences, The University of Western Australia, Crawley, WA, Australia
- Department of Electrical, Electronic and Computer Engineering, University of Western Australia, Perth, 6009, Australia
- Contributed equally
| | - Sophia Nimphius
- School of Medical and Health Sciences, Edith Cowan University, Joondalup, 6027, Australia
| | - Barry Cense
- Department of Electrical, Electronic and Computer Engineering, University of Western Australia, Perth, 6009, Australia
- Department of Mechanical Engineering, Yonsei University, Seoul, 03722, Republic of Korea
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Maroto-Izquierdo S, McBride JM, Gonzalez-Diez N, García-López D, González-Gallego J, de Paz JA. Comparison of Flywheel and Pneumatic Training on Hypertrophy, Strength, and Power in Professional Handball Players. Res Q Exerc Sport 2022; 93:1-15. [PMID: 32669052 DOI: 10.1080/02701367.2020.1762836] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Accepted: 04/27/2020] [Indexed: 06/11/2023]
Abstract
Purpose: The mechanical properties of resistance-training machines are a variable that may help to optimize sports performance and injury prevention protocols. The purpose of this study was to examine two non-gravity-dependent training modalities on muscle structure and function. Methods: Eighteen professional handball players were randomly divided into two experimental groups: 1) iso-inertial flywheel training (FW) and 2) pneumatic resistance training (PN). Participants in both groups completed twelve training sessions in six weeks consisting of three movements (lateral raise, internal and external rotation). Four sets of seven repetitions for each movement were performed during each session. Before and after training subscapularis and deltoid (anterior, middle, posterior) muscle thickness was measured. Isokinetic torque and power during internal and external rotation at 60, 180, and 240 deg·s-1 was measured as well. Throwing speed was assessed before and after training while both sitting and standing situations. Results: Both groups showed similar significant increases in throwing speed and internal and external rotation peak torque, average and peak power at all angular velocities. Anterior and middle deltoid muscle thickness changes were greater after training in FW (20 and 22%) in comparison to PN (14 and 7%, respectively). Conclusions: In summary, both flywheel and pneumatic training resulted in similar increases in shoulder strength and power and throwing speed. However, flywheel training appeared to possibly result in a slightly greater level of muscle hypertrophy of the anterior and middle deltoid. Non-gravity dependent training appears to induce changes that would be beneficial to sports performance and perhaps injury prevention.
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McBride JM, Hackmann MJ, Nimphius S, Cense B. In vivo PS-OCT needle probe scan of human skeletal muscle. Biomed Opt Express 2022; 13:1386-1397. [PMID: 35414965 PMCID: PMC8973164 DOI: 10.1364/boe.446169] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 01/13/2022] [Accepted: 02/02/2022] [Indexed: 05/25/2023]
Abstract
Polarization-sensitive optical coherence tomography (PS-OCT) derived birefringence values effectively identify skeletal muscle structural disruption due to muscular dystrophy and exercise-related muscle damage in animal models in ex vivo tissue. The purpose of this investigation was to determine if a PS-OCT needle probe inserted into the leg of a human subject could accurately identify various anatomical structures with implications for use as a diagnostic tool for the determination of skeletal muscle pathology. A healthy middle-aged subject participated in this study. A custom-built PS-OCT system was interfaced with a side-viewing fiber-optic needle probe inserted into the subject's vastus lateralis muscle via a motorized stage for 3D data acquisition via rotation and stepwise pullback. The deepest recorded PS-OCT images correspond to a depth of 6 mm beneath the dermis with structural images showing uniform, striated muscle tissue. Multiple highly birefringent band-like structures with definite orientation representing connective tissue of the superficial aponeurosis appeared as the depth of the needle decreased. Superficial to these structures the dominating appearance was that of adipose tissue and low birefringent but homogeneous scattering tissue. The data indicate that a PS-OCT needle probe can be inserted into live human skeletal muscle for the identification of relevant anatomical structures that could be utilized to diagnose significant skeletal muscle pathology.
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Affiliation(s)
- Jeffrey M. McBride
- Department of Health & Exercise Science, Appalachian State University, Boone, NC 28608, USA
- School of Medical and Health Sciences, Edith Cowan University, Joondalup, 6027, Australia
- Contributed equally
| | - Michael J. Hackmann
- School of Human Sciences, The University of Western Australia, Crawley, WA, Australia
- Department of Electrical, Electronic and Computer Engineering, University of Western Australia, Perth, 6009, Australia
- Contributed equally
| | - Sophia Nimphius
- School of Medical and Health Sciences, Edith Cowan University, Joondalup, 6027, Australia
| | - Barry Cense
- Department of Electrical, Electronic and Computer Engineering, University of Western Australia, Perth, 6009, Australia
- Department of Mechanical Engineering, Yonsei University, Seoul, 03722, Republic of Korea
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Abstract
The current investigation examined muscle-tendon unit kinematics and kinetics in human participants asked to perform a hopping task for maximal performance with variational preceding milieu. Twenty-four participants were allocated post-data collection into those participants with an average hop height of higher (HH) or lower (LH) than 0.1 m. Participants were placed on a customized sled at a 20º angle while standing on a force plate. Participants used their dominant ankle for all testing and their knee was immobilized and thus all movement involved only the ankle joint and corresponding propulsive unit (triceps surae muscle complex). Participants were asked to perform a maximal effort during a single dynamic countermovement hop (CMH) and drop hops from 10 cm (DH10) and 50 cm (DH50). Three-dimensional motion analysis was performed by utilizing an infrared camera VICON motion analysis system and a corresponding force plate. An ultrasound probe was placed on the triceps surae muscle complex for muscle fascicle imaging. HH hopped significantly higher in all hopping tasks in comparison to LH. In addition, the HH group concentric ankle work was significantly higher in comparison to LH during all of the hopping tasks. Active muscle work was significantly higher in HH in comparison to LH as well. Tendon work was not significantly different between HH and LH. Active muscle work was significantly correlated with hopping height (r = 0.97) across both groups and hopping tasks and contributed more than 50% of the total work. The data indicates that humans primarily use a motor-driven system and thus it is concluded that muscle actuators and not springs maximize performance in hopping locomotor tasks in humans.
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Affiliation(s)
- Jeffrey M McBride
- Neuromuscular & Biomechanics Laboratory, Beaver College of Health Sciences, Department of Health & Exercise Science, Appalachian State University, North Carolina, USA
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Bruce AS, Howard JS, VAN Werkhoven H, McBride JM, Needle AR. The Effects of Transcranial Direct Current Stimulation on Chronic Ankle Instability. Med Sci Sports Exerc 2020; 52:335-344. [PMID: 31453883 DOI: 10.1249/mss.0000000000002129] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
PURPOSE Given maladaptive neuroplasticity after musculoskeletal injury, interventions capable of restoring corticospinal excitability should be considered. We therefore aimed to determine if a 4-wk intervention of anodal transcranial direct current stimulation (aTDCS) with eccentric exercise would improve neural excitability, functional performance, and patient-reported function in individuals with chronic ankle instability (CAI). METHODS Twenty-six individuals with CAI were recruited to undergo 4 wk of eccentric evertor strengthening. Subjects were randomized into aTDCS (n = 13) and sham (n = 13) groups, where the aTDCS group received 18 min of aTDCS (1.5 mA) over the primary motor cortex. Participants were assessed for cortical excitability, dynamic balance, muscle activation, functional performance, strength, and patient-reported function at baseline, week 2, week 4, and week 6. RESULTS Twenty-two subjects completed the training and test sessions. Cortical excitability (resting motor threshold) to peroneus longus in aTDCS increased from baseline (36.92 ± 11.53) to week 6 (32.91 ± 12.33, P = 0.024), whereas sham increased excitability from baseline (36.67 ± 12.74) to week 2 (27.86 ± 14.69, P = 0.007), but decreased at week 4 (35.63 ± 13.10, P = 0.022) and week 6 (35.99 ± 13.52, P = 0.006). Dynamic balance and muscle activation also improved in the aTDCS group from baseline to week 6 (P = 0.034). Functional performance on a side-hop test increased in all participants from baseline to week 2 (P = 0.003). The aTDCS group had decreased perceived disablement from week 2 (18.09 ± 6.41) to week 4 (15.55 ± 4.82, P = 0.046), whereas the sham group reported increased disablement from baseline (17.91 ± 4.59) to week 2 (21.00 ± 8.52, P = 0.047). CONCLUSIONS Our results provide preliminary evidence that 4 wk of eccentric training with aTDCS improves cortical excitability, functional performance, and patient-reported function in individuals with CAI. These data are the first to show the efficacy of noninvasive brain stimulation therapies in patients with musculoskeletal injury, and demonstrate the link between improved neural excitability and functional outcomes.
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Affiliation(s)
- Amelia S Bruce
- Department of Health and Exercise Science, Appalachian State University, Boone, NC
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Needle AR, McAlister MK, Felpel ZJ, McBride JM. Use of an Instrumented Ankle Arthrometer and External Strain Gauge to Assess Ankle Dorsiflexion Motion and Plantarflexor Stiffness. J Am Podiatr Med Assoc 2020; 110:436387. [PMID: 32556228 DOI: 10.7547/18-023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND Ankle dorsiflexion motion and plantarflexor stiffness measurement offer clinical insight into the assessment and treatment of musculoskeletal and neurologic disorders. We aimed to determine reliability and concurrent validity of an ankle arthrometer in quantifying dorsiflexion motion and plantarflexor stiffness. METHODS Ten healthy individuals were assessed for dorsiflexion motion and plantarflexor stiffness using an ankle arthrometer with a 6 degree-of-freedom kinematic linkage system and external strain gauge to apply dorsiflexion torque. Two investigators each performed five loads to the ankle at different combinations of loads (10 or 20 Nm), rates (2.5 or 5 Nm/sec), and knee angles (10° or 20°). Anteroposterior displacement and inversion-eversion rotation were also assessed with arthrometry, and functional dorsiflexion motion was assessed with the weightbearing lunge (WBL) test. RESULTS Good-to-excellent intrarater reliability was observed for peak dorsiflexion (intraclass correlation coefficient [ICC][2,k] = 0.949-0.988) and plantarflexor stiffness (ICC[2,k] = 0.761-0.984). Interrater reliability was good to excellent for peak dorsiflexion (ICC[2,1] = 0.766-0.910) and poor to excellent for plantarflexor stiffness (ICC[2,1] = 0.275-0.914). Reliability was best for 20-Nm loads at 5 Nm/sec. Strong correlations were observed between peak dorsiflexion and anteroposterior displacement (r = 0.666; P = 0.035) and WBL distance (r = -0.681; P = 0.036). CONCLUSIONS Using an ankle arthrometer to assess peak dorsiflexion and plantarflexor stiffness seems reliable when performed to greater torques with faster speeds; and offers consistency with functional measures. Use of this readily available tool may benefit clinicians attempting to quantify equinus and dorsiflexion deficits in pathological populations.
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Affiliation(s)
- Alan R Needle
- Department of Health and Exercise Science, Appalachian State University, Boone, NC
| | - Maurice K McAlister
- Department of Health and Exercise Science, Appalachian State University, Boone, NC
| | - Zachary J Felpel
- Department of Health and Exercise Science, Appalachian State University, Boone, NC
| | - Jeffrey M McBride
- Department of Health and Exercise Science, Appalachian State University, Boone, NC
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Nimphius S, McBride JM, Rice PE, Goodman-Capps CL, Capps CR. Comparison of Quadriceps and Hamstring Muscle Activity during an Isometric Squat between Strength-Matched Men and Women. J Sports Sci Med 2019; 18:101-108. [PMID: 30787657 PMCID: PMC6370970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 12/17/2018] [Indexed: 06/09/2023]
Abstract
The primary purpose of this investigation was to determine whether strength-matched men and women exhibit a different magnitude and ratio of leg muscle activity during a maximal voluntary isometric squat. The secondary purpose was to assess the effect of normalization method on differences in strength between men and women. Thirty-two men (n = 16) and women (n = 16) were successfully strength-matched (≤10% difference) by maximal force produced during an isometric squat (IS) when normalized to body weight. Subjects first performed a maximal isometric knee extension (IKE) and knee flexion (IKF) followed by the IS and muscle activity (EMGmax) was recorded for the vastus medialis (VMO), vastus lateralis (VL), semitendinosus (ST) and biceps femoris (BF). Muscle activity during the IS was expressed relative to the maximums observed during the IKE and IKF (%EMGmax). The results indicate that VMO, VL, ST and BF %EMGmax were not significantly different (p > 0.05) between men and women during the IS (Men VMO = 136.7 ± 24.9%, Women VMO = 157.1 ± 59.8%, Men VL = 126.2 ± 38.2%, Women VL = 128.1 ± 35.5%, Men ST = 25.5 ± 13.6%, Women ST = 25.2 ± 21.8%, Men BF = 46.1 ± 26.0%, Women BF = 42.2 ± 24.8%). Furthermore, the VMO:VL and hamstring to quadriceps (H:Q) %EMGmax ratio were not significantly different between groups in the IS (Men VMO:VL = 1.15 ± 0.28, Women VMO:VL = 1.22 ± 0.26, Men H:Q = 0.28 ± 0.14, Women H:Q = 0.24 ± 0.20). This investigation indicates that the magnitude of muscle activity and the ratios examined are not significantly different between men and women in a maximal voluntary isometric squat when matched for normalized strength. Future investigations should consider subject strength and normalization procedures in the experimental design to elucidate possible sex differences in neuromuscular performance capabilities.
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Affiliation(s)
- Sophia Nimphius
- Centre for Exercise and Sports Science Research, School of Medical and Health Sciences, Edith Cowan University, Joondalup, Australia
| | - Jeffrey M McBride
- Neuromuscular and Biomechanics Laboratory, Department of Health and Exercise Science, Appalachian State University, Boone, North Carolina, USA
| | - Paige E Rice
- Centre for Exercise and Sports Science Research, School of Medical and Health Sciences, Edith Cowan University, Joondalup, Australia
- Neuromuscular and Biomechanics Laboratory, Department of Health and Exercise Science, Appalachian State University, Boone, North Carolina, USA
| | - Courtney L Goodman-Capps
- Neuromuscular and Biomechanics Laboratory, Department of Health and Exercise Science, Appalachian State University, Boone, North Carolina, USA
| | - Christopher R Capps
- Neuromuscular and Biomechanics Laboratory, Department of Health and Exercise Science, Appalachian State University, Boone, North Carolina, USA
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Rice PE, Needle AR, Leicht ZS, Zwetsloot KA, McBride JM. Bone health, muscle properties and stretch-shortening cycle function of young and elderly males. J Musculoskelet Neuronal Interact 2019; 19:389-395. [PMID: 31789290 PMCID: PMC6944796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The aim of this study was to examine bone, muscle, strength and stretch-shortening cycle (SSC) performance in young and elderly individuals with an ankle model to elucidate potential effects of ageing that have been suggested to influence fall risk. Moderately active young (n=10; age=22.3±1.3 yrs) and elderly (n=8; age=67.5±3.3 yrs) males completed a peripheral quantitative computed tomography scan on the dominant lower leg, maximal voluntary isometric plantarflexions (MVIP) and SSC tasks: a countermovement hop and drop hops from three different heights. Bone stress-strain index at 14% of the lower leg and muscle density, muscle cross-sectional area and muscle+bone cross-sectional area at 66% of the lower leg were all significantly greater (p≤0.05) in younger males than elderly males. Younger males also had significantly greater rate of force development and peak force during the MVIP when compared to the elderly. Younger males achieved significantly higher forces, velocities and hop heights during all SSC tasks than elderly males. Such information provides support for greater specificity in exercise interventions that prevent lower leg morphological and functional decrements in the ageing population.
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Affiliation(s)
- Paige E. Rice
- Centre for Exercise and Sports Science Research, Edith Cowan University, Joondalup, Australia,Neuromuscular & Biomechanics Laboratory, Department of Health and Exercise Science, Appalachian State University, Boone USA,Corresponding author: Paige E. Rice, MS, School of Medical and Health Sciences, Centre for Exercise and Sport Science Research, Edith Cowan University, Joondalup, WA, AUS 6027 E-mail:
| | - Alan R. Needle
- Neuromuscular & Biomechanics Laboratory, Department of Health and Exercise Science, Appalachian State University, Boone USA
| | - Zachary S. Leicht
- Neuromuscular & Biomechanics Laboratory, Department of Health and Exercise Science, Appalachian State University, Boone USA
| | - Kevin A. Zwetsloot
- Neuromuscular & Biomechanics Laboratory, Department of Health and Exercise Science, Appalachian State University, Boone USA
| | - Jeffrey M. McBride
- Neuromuscular & Biomechanics Laboratory, Department of Health and Exercise Science, Appalachian State University, Boone USA
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Rice PE, Gurchiek RD, McBride JM. Physiological and Biomechanical Responses to an Acute Bout of High Kicking in Dancers. J Strength Cond Res 2018; 32:2954-2961. [DOI: 10.1519/jsc.0000000000002748] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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McMenamin PG, McLachlan J, Wilson A, McBride JM, Pickering J, Evans DJR, Winkelmann A. Do we really need cadavers anymore to learn anatomy in undergraduate medicine? Med Teach 2018; 40:1020-1029. [PMID: 30265177 DOI: 10.1080/0142159x.2018.1485884] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
With the availability of numerous adjuncts or alternatives to learning anatomy other than cadavers (medical imaging, models, body painting, interactive media, virtual reality) and the costs of maintaining cadaver laboratories, it was considered timely to have a mature debate about the need for cadavers in the teaching of undergraduate medicine. This may be particularly pertinent given the exponential growth in medical knowledge in other disciplines, which gives them valid justification for time in already busy medical curricula. In this symposium, the pros and cons of cadaver use in modern medical curricula were debated and audience participation encouraged.
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Affiliation(s)
- P G McMenamin
- a Department of Anatomy & Developmental Biology, Faculty of Medicine, Nursing and Health Sciences , Monash University , Melbourne , Australia
| | | | - A Wilson
- c Department of Cell and Molecular Medicine , Rush University , Chicago , IL , USA
| | - J M McBride
- d Cleveland Clinic Lerner College of Medicine , Cleveland Clinic , Cleveland , OH , USA
| | - J Pickering
- e Division of Anatomy, Leeds Institute of Medical Education, School of Medicine , University of Leeds , Leeds , UK
| | - D J R Evans
- f Developmental Tissue Biology, Academic Division, The University of Newcastle (UON) , Callaghan , Australia
| | - A Winkelmann
- g Institut für Anatomie, Medizinische Hochschule Brandenburg - Theodor Fontane , Neuruppin , Germany
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Stirling AM, McBride JM, Merritt EK, Needle AR. Nervous system excitability and joint stiffness following short-term dynamic ankle immobilization. Gait Posture 2018; 59:46-52. [PMID: 28987766 DOI: 10.1016/j.gaitpost.2017.09.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 09/18/2017] [Accepted: 09/22/2017] [Indexed: 02/02/2023]
Abstract
Joint immobilization has been demonstrated to modify neural excitability in subsets of healthy populations, leading to disinhibition of cortical and reflexive pathways. However, these findings may have limited clinical application as most models have investigated casting and rigid immobilization, while many musculoskeletal injuries often utilize dynamic immobilization devices such as boot immobilizers and pneumatic splints that allow for modified ambulation. We therefore aimed to determine the short-term effects of ambulation in ankle immobilization devices on nervous system excitability and stiffness in able-bodied individuals. A repeated-measures design was implemented where 12 healthy individuals were tested for cortical excitability to the ankle musculature using transcranial magnetic stimulation, reflexive excitability using the Hoffmann reflex, and ankle joint stiffness using arthrometry before and after 30min of ambulation with a boot immobilizer, pneumatic leg splint, or barefoot. Motor evoked potential (MEP), cortical silent period (CSP), Hmax to Mmax ratio, and ankle joint displacement were extracted as dependent variables. Results indicated that despite the novel motor demands of walking in immobilization devices, no significant changes in cortical excitability (F≥0.335, P≥0.169), reflexive excitability (F≥0.027, P≥0.083), or joint stiffness (F≥0.558, P≥0.169) occurred. These findings indicate that short-term ambulation in dynamic immobilization devices does not modify neural excitability despite forced constraints on the sensorimotor system. We may therefore conclude that modifications to neural excitability in previous immobilization models are mediated by long-term nervous system plasticity rather than acute mechanisms, and there appear to be no robust changes in corticomotor or spinal excitability acutely posed by ambulation with immobilization devices.
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Affiliation(s)
- Alyssa M Stirling
- Department of Health & Exercise Science, Appalachian State University, Boone, NC, USA
| | - Jeffrey M McBride
- Department of Health & Exercise Science, Appalachian State University, Boone, NC, USA
| | - Edward K Merritt
- Department of Kinesiology, Southwestern University, Georgetown, TX, USA
| | - Alan R Needle
- Department of Health & Exercise Science, Appalachian State University, Boone, NC, USA.
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Rice PE, van Werkhoven H, Dejournette DJ, Gurchiek RD, Mackall JW, McBride JM. A Comparison of Musculo-Articular Stiffness and Maximal Isometric Plantar Flexion and Knee Extension Force in Dancers and Untrained Individuals. J Dance Med Sci 2017; 21:144-150. [DOI: 10.12678/1089-313x.21.4.144] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Paige E. Rice
- Neuromuscular & Biomechanics Laboratory, Department of Health & Exercise Science, Appalachian State University, Boone, North Carolina
| | - Herman van Werkhoven
- Neuromuscular & Biomechanics Laboratory, Department of Health & Exercise Science, Appalachian State University, Boone, North Carolina
| | - Denzel J. Dejournette
- Neuromuscular & Biomechanics Laboratory, Department of Health & Exercise Science, Appalachian State University, Boone, North Carolina
| | - Reed D. Gurchiek
- Neuromuscular & Biomechanics Laboratory, Department of Health & Exercise Science, Appalachian State University, Boone, North Carolina
| | - John W. Mackall
- Neuromuscular & Biomechanics Laboratory, Department of Health & Exercise Science, Appalachian State University, Boone, North Carolina
| | - Jeffrey M. McBride
- Neuromuscular & Biomechanics Laboratory, Department of Health & Exercise Science, Appalachian State University, Boone, North Carolina
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Gurchiek RD, McGinnis RS, Needle AR, McBride JM, van Werkhoven H. The use of a single inertial sensor to estimate 3-dimensional ground reaction force during accelerative running tasks. J Biomech 2017; 61:263-268. [PMID: 28830590 DOI: 10.1016/j.jbiomech.2017.07.035] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 06/27/2017] [Accepted: 07/22/2017] [Indexed: 11/16/2022]
Abstract
The purpose of this investigation was to determine the feasibility of using a single inertial measurement unit (IMU) placed on the sacrum to estimate 3-dimensional ground reaction force (F) during linear acceleration and change of direction tasks. Force plate measurements of F and estimates from the proposed IMU method were collected while subjects (n=15) performed a standing sprint start (SS) and a 45° change of direction task (COD). Error in the IMU estimate of step-averaged component and resultant F was quantified by comparison to estimates from the force plate using Bland-Altman 95% limits of agreement (LOA), root mean square error (RMSE), Pearson's product-moment correlation coefficient (r), and the effect size (ES) of the differences between the two systems. RMSE of the IMU estimate of step-average F ranged from 37.70 N to 77.05 N with ES between 0.04 and 0.47 for SS while for COD, RMSE was between 54.19 N to 182.92 N with ES between 0.08 and 1.69. Correlation coefficients between the IMU and force plate measurements were significant (p≤0.05) for all values (r=0.53 to 0.95) except the medio-lateral component of step-average F. The average angular error in the IMU estimate of the orientation of step-average F was ≤10° for all tasks. The results of this study suggest the proposed IMU method may be used to estimate sagittal plane components and magnitude of step-average F during a linear standing sprint start as well as the vertical component and magnitude of step-average F during a 45° change of direction task.
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Affiliation(s)
- Reed D Gurchiek
- Department of Health and Exercise Science, Appalachian State University, Boone, NC 28608, USA.
| | - Ryan S McGinnis
- Department of Electrical and Biomedical Engineering, University of Vermont, Burlington, VT 05405, USA
| | - Alan R Needle
- Department of Health and Exercise Science, Appalachian State University, Boone, NC 28608, USA
| | - Jeffrey M McBride
- Department of Health and Exercise Science, Appalachian State University, Boone, NC 28608, USA
| | - Herman van Werkhoven
- Department of Health and Exercise Science, Appalachian State University, Boone, NC 28608, USA
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Sommerfield LM, McAnulty SR, McBride JM, Zwetsloot JJ, Austin MD, Mehlhorn JD, Calhoun MC, Young JO, Haines TL, Utter AC. Validity of Urine Specific Gravity When Compared With Plasma Osmolality as a Measure of Hydration Status in Male and Female NCAA Collegiate Athletes. J Strength Cond Res 2016; 30:2219-25. [PMID: 26694503 DOI: 10.1519/jsc.0000000000001313] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Sommerfield, LM, McAnulty, SR, McBride, JM, Zwetsloot, JJ, Austin, MD, Mehlhorn, JD, Calhoun, MC, Young, JO, Haines, TL, and Utter, AC. Validity of urine specific gravity when compared with plasma osmolality as a measure of hydration status in male and female NCAA collegiate athletes. J Strength Cond Res 30(8): 2219-2225, 2016-The purpose of this study was to evaluate the response of urine specific gravity (Usg) and urine osmolality (Uosm) when compared with plasma osmolality (Posm) from euhydration to 3% dehydration and then a 2-hour rehydration period in male and female collegiate athletes. Fifty-six National Collegiate Athletic Association (NCAA) wrestlers (mean ± SEM); height 1.75 ± 0.01 m, age 19.3 ± 0.2 years, and body mass (BM) 78.1 ± 1.8 kg and 26 NCAA women's soccer athletes; height 1.64 ± 0.01 m, age 19.8 ± 0.3 years, and BM 62.2 ± 1.2 kg were evaluated. Hydration status was obtained by measuring changes in Posm, Uosm, Usg, and BM. Male and female subjects dehydrated to achieve an average BM loss of 2.9 ± 0.09% and 1.9 ± 0.03%, respectively. Using the medical diagnostic decision model, the sensitivity of Usg was high in both the hydrated and dehydrated state for males (92%) and females (80%). However, the specificity of Usg was low in both the hydrated and dehydrated states for males (10 and 6%, respectively) and females (29 and 40%, respectively). No significant correlations were found between Usg and Posm during either the hydrated or dehydrated state for males or females. Based on these results, the use of Usg as a field measure of hydration status in male and female collegiate athletes should be used with caution. Considering that athletes deal with hydration status on a regular basis, the reported low specificity of Usg suggests that athletes could be incorrectly classified leading to the unnecessary loss of competition.
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Affiliation(s)
- Lesley M Sommerfield
- Department of Health and Exercise Science, Appalachian State University, Boone, North Carolina
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Rice PE, Goodman CL, Capps CR, Triplett NT, Erickson TM, McBride JM. Force- and power-time curve comparison during jumping between strength-matched male and female basketball players. Eur J Sport Sci 2016; 17:286-293. [PMID: 27691454 DOI: 10.1080/17461391.2016.1236840] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
The purpose of this study was to compare force- and power-time curve variables during jumping between Division I strength-matched male and female basketball athletes. Males (n = 8) and females (n = 8) were strength matched by testing a one-repetition maximum (1RM) back squat. 1RM back squat values were normalised to body mass in order to demonstrate that strength differences were a function of body mass alone. Subjects performed three countermovement jumps (CMJ) at maximal effort. Absolute and relative force- and power-time curve variables from the CMJs were analysed between males and females. Average force- and power-time curves were generated for all subjects. Jump height was significantly greater (p ≤ .05) in males than females. Absolute force was higher in males during the concentric phase, but not significantly different (p ≥ .05) when normalised to body mass. Significance was found in absolute concentric impulse between sexes, but not when analysed relative to body mass. Rate of force development, rate of power development, relative peak force, and work were not significantly different between sexes. Males had significantly greater impulse during the eccentric phase as well as peak power (PP) during the concentric phase of the CMJ than did females in both absolute and relative terms. It is concluded that sex differences are not a determining factor in measured force during a CMJ when normalised to body mass between strength-matched subjects. However, eccentric phase impulse and concentric phase PP appear to be influenced by sex differences independent of matching strength levels.
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Affiliation(s)
- Paige E Rice
- a Neuromuscular & Biomechanics Laboratory, Department of Health, Leisure & Exercise Science , Appalachian State University , Boone , NC 28607 , USA
| | - Courtney L Goodman
- a Neuromuscular & Biomechanics Laboratory, Department of Health, Leisure & Exercise Science , Appalachian State University , Boone , NC 28607 , USA
| | - Christopher R Capps
- a Neuromuscular & Biomechanics Laboratory, Department of Health, Leisure & Exercise Science , Appalachian State University , Boone , NC 28607 , USA
| | - N Travis Triplett
- a Neuromuscular & Biomechanics Laboratory, Department of Health, Leisure & Exercise Science , Appalachian State University , Boone , NC 28607 , USA
| | - Travis M Erickson
- a Neuromuscular & Biomechanics Laboratory, Department of Health, Leisure & Exercise Science , Appalachian State University , Boone , NC 28607 , USA
| | - Jeffrey M McBride
- a Neuromuscular & Biomechanics Laboratory, Department of Health, Leisure & Exercise Science , Appalachian State University , Boone , NC 28607 , USA
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Lidstone DE, van Werkhoven H, Stewart JA, Gurchiek R, Burris M, Rice P, Feimster G, McBride JM. Medial gastrocnemius muscle-tendon interaction and architecture change during exhaustive hopping exercise. J Electromyogr Kinesiol 2016; 30:89-97. [PMID: 27362587 DOI: 10.1016/j.jelekin.2016.06.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 06/11/2016] [Accepted: 06/15/2016] [Indexed: 10/21/2022] Open
Abstract
BACKGROUND Previous literature has shown in vivo changes in muscle-tendon interaction during exhaustive stretch-shortening cycle (SSC) exercise. It is unclear whether these changes in muscle-tendon length during exhaustive SSC exercise are associated with changes in mechanical efficiency (ME). The purpose of the study was to investigate whether changes in platarflexor contractile component (CC) length, tendon length, and changes in plantarflexor muscle activity could explain reduction in ME during exhaustive SSC exercise. METHODS Eight males participated in an exhaustive hopping task to fatigue. Mechanical work and energy expenditure were calculated at different time-points during the hopping task. Furthermore, hopping kinetics and kinematics, medial gastrocnemius (MG) muscle activity, and in vivo ultrasound of the MG were also collected at different time-points throughout the hopping task. RESULTS ME did not change during the hopping protocol despite shorter tendon and longer CC lengths as subjects approached exhaustion. Percent decreases in pennation angle and muscle thickness were most strongly correlated to time to exhaustion (r=0.94, p⩽0.05; r=0.87, p⩽0.05; respectively). Percent changes in CC length change and pennation angle were strongly correlated to percent decrease in maximal voluntary isometric plantarflexion (MVIP) force (r=-0.71, p⩽0.04; r=0.70, p⩽0.05; respectively). Braking/push-off EMG ratio increased from initial pre-fatigue values to all other time points showing neuromuscular adaptations to altered muscle lengths. CONCLUSION Findings from the current study suggest that changes in CC and tendon lengths occur during repetitive hopping to exhaustion, with the amount change strongly related to time to exhaustion. ME of hopping remained unchanged in the presence of altered CC and tendon lengths.
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Affiliation(s)
- Daniel E Lidstone
- Department of Health & Exercise Science, Appalachian State University, Holmes Convocation Center, 111 Rivers St, Boone, NC 28608, USA.
| | - Herman van Werkhoven
- Department of Health & Exercise Science, Appalachian State University, Holmes Convocation Center, 111 Rivers St, Boone, NC 28608, USA
| | - Justin A Stewart
- Department of Health & Exercise Science, Appalachian State University, Holmes Convocation Center, 111 Rivers St, Boone, NC 28608, USA
| | - Reed Gurchiek
- Department of Health & Exercise Science, Appalachian State University, Holmes Convocation Center, 111 Rivers St, Boone, NC 28608, USA
| | - Madison Burris
- Department of Health & Exercise Science, Appalachian State University, Holmes Convocation Center, 111 Rivers St, Boone, NC 28608, USA
| | - Paige Rice
- Department of Health & Exercise Science, Appalachian State University, Holmes Convocation Center, 111 Rivers St, Boone, NC 28608, USA
| | - Garrett Feimster
- Department of Health & Exercise Science, Appalachian State University, Holmes Convocation Center, 111 Rivers St, Boone, NC 28608, USA
| | - Jeffrey M McBride
- Department of Health & Exercise Science, Appalachian State University, Holmes Convocation Center, 111 Rivers St, Boone, NC 28608, USA
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20
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Kijowksi KN, Capps CR, Goodman CL, Erickson TM, Knorr DP, Triplett NT, Awelewa OO, McBride JM. Short-term Resistance and Plyometric Training Improves Eccentric Phase Kinetics in Jumping. J Strength Cond Res 2016. [PMID: 26203736 DOI: 10.1519/jsc.0000000000000904] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The purpose of this investigation was to examine the effect of an abbreviated resistance and plyometric training program on force- and power-time curve variables during jumping. Nineteen male subjects were assigned to either a training (n = 9) or control group (n = 10). Training consisted of performing 3 sets of 3 repetition squats (90% of 1 repetition maximum [RM]) and 5 sets of 6 repetition drop jumps from 40 cm twice per week for 4 weeks. A 1RM in the squat and countermovement (CMJ) and static jump (SJ) performance was assessed before and after training. Several variables were analyzed for individual subject force- and power-time curves for the jumps. Average force- and power-time curves for all subjects combined were also analyzed. Absolute and relative squat strength significantly increased in training group (p ≤ 0.05). Calculation of variables from individual subject force-time curves during the CMJ indicated a significant decrease in eccentric time, minimum force, and eccentric impulse and significant increase in eccentric rate of force development in training group. Analysis of individual power-time curves in the CMJ also revealed a significant decrease in minimum power and eccentric work and a significant increase in eccentric rate of power development. No significant changes occurred in the variables measured for the SJ. The results of this study indicate that short-term strength and plyometric training may preferentially influence eccentric performance variables during jumping in comparison with longer term training enhancements to the concentric phase performance.
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Affiliation(s)
- Kevin N Kijowksi
- Neuromuscular & Biomechanics Laboratory, Department of Health, Leisure & Exercise Science, Appalachian State University, Boone, North Carolina
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McBride JM, Davis JA, Alley JR, Knorr DP, Goodman CL, Snyder JG, Battista RA. Index of mechanical efficiency in competitive and recreational long distance runners. J Sports Sci 2014; 33:1388-95. [PMID: 25528888 DOI: 10.1080/02640414.2014.990487] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The purpose of this investigation was to compare external work and net energy expenditure during a bout of repetitive stretch-shortening cycles between competitive and recreational long-distance runners. Participants were divided into either competitive or recreational runners based on their maximal oxygen consumption and self-reported 1600 m times. The stretch-shortening cycle involved a repetitive hopping protocol on a force plate while measuring oxygen consumption and lactate accumulation for a total of 10 min. External work and net energy expenditure were calculated for 3 min after steady state was achieved and the ratio between these variables was utilised as an index of mechanical efficiency. Lower extremity stiffness was calculated during this interval as well. Net energy expenditure was significantly lower in competitive runners (152.6 ± 33.3 kJ) in comparison to recreational runners (200.6 ± 41.4 kJ) (P = 0.02) given similar amounts of external work performed in both groups (competitive runners = 65.6 ± 20.1 kJ, recreational runners = 68.8 ± 12.1 kJ) (P = 0.67). Index of mechanical efficiency was significantly different between competitive runners (43.2 ± 9.0%) and recreational runners (34.8 ± 5.3%) (P = 0.03). No significant differences were found in lower extremity stiffness (P = 0.64). Competitive distance runners can perform similar levels of external work with lower net energy expenditure and thus a higher index of mechanical efficiency during repetitive stretch-shortening cycles in comparison to recreational runners with similar values of lower extremity stiffness. This ability could possibly be due differences in muscle-tendon length changes, muscle pre-activation, cross-bridge potentiation and short-latency reflex responses as a result of training which should be considered for future investigation.
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Affiliation(s)
- Jeffrey M McBride
- a Department of Health, Leisure & Exercise Science , Appalachian State University , Boone , NC , USA
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Vasquez LM, McBride JM, Paul JA, Alley JR, Carson LT, Goodman CL. Effect of Resistance Exercise Performed to Volitional Failure on Ratings of Perceived Exertion. Percept Mot Skills 2013; 117:881-91. [DOI: 10.2466/27.29.pms.117x30z8] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The purpose of this investigation was to assess the effect of resistance exercise performed to volitional failure on ratings of perceived exertion (RPE) using power as an indication of fatigue. 12 male participants ( M age= 21.9 yr., SD = 1.3) performed one set of back squats at three different intensities (50%, 70%, and 90% of one repetition maximum) for both a pre-determined number of repetitions (3) and to volitional failure. RPE was significantly different between sets at 50%, 70%, and 90% when performed to a pre-determined number of repetitions, but not during volitional failure. A decrease in power between the first and the last repetitions in the volitional failure sets suggests that fatigue may confound the relationship between RPE and intensity.
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Affiliation(s)
- Ligia M. Vasquez
- Neuromuscular & Biomechanics Laboratory, Department of Health, Leisure & Exercise Science, Appalachian State University
| | - Jeffrey M. McBride
- Neuromuscular & Biomechanics Laboratory, Department of Health, Leisure & Exercise Science, Appalachian State University
| | - Judith A. Paul
- Neuromuscular & Biomechanics Laboratory, Department of Health, Leisure & Exercise Science, Appalachian State University
| | - Jessica R. Alley
- Neuromuscular & Biomechanics Laboratory, Department of Health, Leisure & Exercise Science, Appalachian State University
| | - Lauren T. Carson
- Neuromuscular & Biomechanics Laboratory, Department of Health, Leisure & Exercise Science, Appalachian State University
| | - Courtney L. Goodman
- Neuromuscular & Biomechanics Laboratory, Department of Health, Leisure & Exercise Science, Appalachian State University
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Hardee JP, Lawrence MM, Zwetsloot KA, Triplett NT, Utter AC, McBride JM. Effect of cluster set configurations on power clean technique. J Sports Sci 2013; 31:488-96. [DOI: 10.1080/02640414.2012.736633] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Hudgins B, Scharfenberg J, Triplett NT, McBride JM. Relationship Between Jumping Ability and Running Performance in Events of Varying Distance. J Strength Cond Res 2013; 27:563-7. [DOI: 10.1519/jsc.0b013e31827e136f] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Haines TL, McBride JM, Triplett NT, Skinner JW, Fairbrother KR, Kirby TJ. A comparison of men's and women's strength to body mass ratio and varus/valgus knee angle during jump landings. J Sports Sci 2011; 29:1435-42. [DOI: 10.1080/02640414.2011.599039] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Tracie L Haines
- Neuromuscular Laboratory, Department of Health, Leisure and Exercise Science, Appalachian State University, Boone, North Carolina, USA
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Abstract
Nine males (age 24.7 ± 2.1 years, height 175.3 ± 5.5 cm, body mass 80.8 ± 7.2 kg, power clean 1-RM 97.1 ± 6.36 kg, squat 1-RM = 138.3 ± 20.9 kg) participated in this study. On day 1, the participants performed a one-repetition maximum (1-RM) in the power clean and the squat. On days 2, 3, and 4, participants performed the power clean, squat or jump squat. Loading for the power clean ranged from 30% to 90% of the participant's power clean 1-RM and loading for the squat and jump squat ranged from 0% to 90% of the participant's squat 1-RM, all at 10% increments. Peak force, velocity, and power were calculated for the bar, body, and system (bar + body) for all power clean, squat, and jump squat trials. Results indicate that peak power for the bar, body, and system is differentially affected by load and movement pattern. When using the power clean, squat or jump squat for training, the optimal load in each exercise may vary. Throwing athletes or weightlifters may be most concerned with bar power, but jumpers or sprinters may be more concerned with body or system power. Thus, the exercise type and load vary according to the desired stimulus.
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Affiliation(s)
- Jeffrey M McBride
- Neuromuscular Laboratory, Department of Health, Leisure, and Exercise Science, Appalachian State University, Boone, North Carolina 28608, USA.
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Abstract
The load that maximizes power output in the jump squat (JS) in college-aged athletic males has been reported to be 0% of 1 repetition maximum [1RM] squat strength) or in other words body mass. No data exist concerning adolescent athletic males. In addition, strength levels have been theorized to possibly affect the load that maximizes power output in the JS. The purpose of this investigation was to identify the load that maximizes power output in the JS in adolescent athletic men, and concurrently describe their strength level and its effect on the load that maximizes power output. Eleven high-school male athletes were tested on 2 occasions, first determining their 1RM in the squat (1RM = 141.14 ± 28.08 kg; squat 1RM-to-body mass ratio = 1.76 ± 0.15) and then performing JS testing at loads equal to 0% (body mass), 20, 40, 60, and 80% of squat 1RM. Peak power (PP), peak force, peak velocity (PV), and peak displacement were measured at each load. Jump squat at the 0% load produced significantly (p ≤ 0.05) higher PP, PV, and peak displacement in comparison with the 40, 60, and 80% loading conditions. It was concluded that the load that maximizes power output in the JS is 0% of 1RM in adolescent athletic men, the same as found in college-aged athletic men. In addition, strength level relative to body mass did not affect the load that maximized power output. Practically, when devising a training program to increase PP, it is important to include JSs at body mass along with traditional strength training at heavier loads to increase power output across the entire loading spectrum.
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Affiliation(s)
- Andrea M Dayne
- Neuromuscular Laboratory, Department of Health, Leisure and Exercise Science, Appalachian State University, Boone, North Carolina, USA
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Snyder JG, Ambegaonkar JP, Winchester JB, McBride JM, Andre MJ, Nelson AG. Efficacy of Cold-Water Immersion in Treating Delayed Onset Muscle Soreness in Male Distance Runners. Med Sci Sports Exerc 2011. [DOI: 10.1249/01.mss.0000402128.66983.f7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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McBride JM, Skinner JW, Schafer PC, Haines TL, Kirby TJ. Comparison of Kinetic Variables and Muscle Activity During a Squat vs. a Box Squat. J Strength Cond Res 2010; 24:3195-9. [DOI: 10.1519/jsc.0b013e3181f6399a] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Nuzzo JL, McBride JM, Dayne AM, Israetel MA, Dumke CL, Triplett NT. Testing of the maximal dynamic output hypothesis in trained and untrained subjects. J Strength Cond Res 2010; 24:1269-76. [PMID: 20386123 DOI: 10.1519/jsc.0b013e3181d68691] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The maximal dynamic output (MDO) hypothesis is a newly proposed concept, which suggests that the muscular system of the lower limbs is designed to produce maximal power output when performing countermovement vertical jumping (CMJ) at body mass as opposed to other loading conditions. However, it is unclear if the MDO concept can be applied to individuals with different levels of maximal strength. The purpose of this investigation was to determine if subjects, who have distinct differences in maximal strength, maximize CMJ power at body mass. Fourteen male strength-power trained subjects (squat 1 repetition maximum (1RM)-to-body mass ratio = 1.96 +/- 0.24) and 6 untrained male subjects (squat 1RM-to-body mass ratio = 0.94 +/- 0.18) completed CMJs with loads that were less than, equal to, and greater than body mass. Loads less than body mass were accomplished with a custom-designed unloading apparatus, and loads greater than body mass were accomplished with a barbell and weights. In both groups, mean values for CMJ peak and mean power were greatest during the body mass jump. Power outputs at body mass were significantly different (p <or= 0.05) than power outputs at various conditions of loading and unloading. These data support the MDO hypothesis and its application to individuals with significantly different 1RM-to-body mass ratios. Additionally, these data further support the idea that body mass CMJs are a theoretically sound way to train for power because of the maximal power outputs that are produced during this condition.
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Affiliation(s)
- James L Nuzzo
- Department of Exercise and Rehabilitative Sciences, Slippery Rock University, Slippery Rock, Pennsylvania, USA.
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Israetel MA, McBride JM, Nuzzo JL, Skinner JW, Dayne AM. Kinetic and Kinematic Differences Between Squats Performed With and Without Elastic Bands. J Strength Cond Res 2010; 24:190-4. [DOI: 10.1519/jsc.0b013e31819b7995] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Dayne A, Dayne AM, Nuzzo JL, McBride JM, Burr A, Travis Triplett N. Power Output In The Jump Squat In Adolescent Male Athletes. J Strength Cond Res 2010. [DOI: 10.1097/01.jsc.0000367094.65757.8f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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McBride JM, Nuzzo JL, Dayne AM, Israetel MA, Nieman DC, Triplett NT. Effect of an acute bout of whole body vibration exercise on muscle force output and motor neuron excitability. J Strength Cond Res 2009; 24:184-9. [PMID: 19816218 DOI: 10.1519/jsc.0b013e31819b79cf] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The purpose of the current investigation was to assess the effect of an acute bout of whole body vibration (WBV) exercise on muscle force output and motor neuron excitability. Nineteen recreationally trained college-aged males were randomly assigned to a WBV (n = 10) or a sham (S, n = 9) group. The WBV group completed a series of static, body weight squats on a vibrating platform at 30 Hz and an amplitude of approximately 3.5 mm (vertical), whereas the S group performed the same series of exercises but without vibration. Measurements were performed before (Pre) and then immediately post-exercise (Imm Post), 8 minutes post-exercise (8-Min Post), or 16 minutes post-exercise (16-Min Post) during 3 different testing sessions. The measurements involved a ballistic isometric maximum voluntary contraction (MVC) of the triceps surae muscle complex and electrical stimulation of the tibial nerve for assessment of motor neuron excitability by analyzing H-reflex and M-wave responses (H(max)/M(max) ratio). Electromyography was also obtained from the triceps surae muscle complex during the MVCs. The WBV group significantly (p < or = 0.05) increased peak force at Imm Post (9.4%) and 8-Min Post (10.4%). No significant change in peak force was observed in the S group. No significant changes were observed in either group for average integrated EMG, H(max)/M(max) ratio, or rate of force development at Imm Post, 8-Min Post, or 16-Min Post. The results from this investigation indicate that an acute bout of static, body weight squat exercises, combined with WBV, increases muscle force output up to 8 minutes post-exercise. However, this increase in muscle force is not accompanied by a significant increase in motor neuron excitability or muscle activation. Thus, it is plausible to use WBV as a method for acute increase in muscle force output for athletes immediately before competition.
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Affiliation(s)
- Jeffrey M McBride
- Neuromuscular Laboratory, Department of Health, Leisure, and Exercise Science, Appalachian State University, Boone, North Carolina, USA.
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McBride JM, Blow D, Kirby TJ, Haines TL, Dayne AM, Triplett NT. Relationship Between Maximal Squat Strength and Five, Ten, and Forty Yard Sprint Times. J Strength Cond Res 2009; 23:1633-6. [DOI: 10.1519/jsc.0b013e3181b2b8aa] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Winchester JB, Porter JM, McBride JM. Changes in bar path kinematics and kinetics through use of summary feedback in power snatch training. J Strength Cond Res 2009; 23:444-54. [PMID: 19209074 DOI: 10.1519/jsc.0b013e318198fc73] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This study investigated kinematic and kinetic variable changes in the power snatch (PS) after 4 weeks of training and the use of summary feedback. Twenty-four collegiate football players participated as subjects in this study. The subjects were pretested for their 1-repetition maximum (1RM) and were separated into feedback (FG; n = 12) and control (CG; n = 12) groups. The FG was provided with augmented feedback (AF) during power snatch training sessions, which took place 3 times per week for 4 weeks. The AF is defined as information that is received in addition to what is naturally available. Variables measured include peak force (PF), peak power (PP), and several kinematic variables at 50, 70, and 90% of the subjects' pre-1RM. The PF was improved at 50% 1RM from 567 +/- 202 to 769 +/- 230 N, at 70% from 725 +/- 186 to 890 +/- 199 N, and at 90% from 822 +/- 197 to 1008 +/- 201 N in the FG (p <or= 0.05). The PP was increased at 50% 1RM from 2061 +/- 562 to 2538 +/- 498 W, at 70% from 2321 +/- 743 to 2754 +/- 629 W, and at 90% from 2076 +/- 437 to 2491 +/- 526 W in the FG (p <or= 0.05). Variables with respect to bar path kinematics improved significantly. No improvements in kinetics or kinematics were noted in the CG. These results indicate that both kinematic and kinetic variables improve through training and AF. Practitioners wishing to improve weightlifting performance should attempt to use evidence-based AF.
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Affiliation(s)
- Jason B Winchester
- School of Recreation, Health, and Tourism, George Mason University, Manassas, Virginia, USA.
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Cormie P, McBride JM, McCaulley GO. Power-time, force-time, and velocity-time curve analysis of the countermovement jump: impact of training. J Strength Cond Res 2009; 23:177-86. [PMID: 19077740 DOI: 10.1519/jsc.0b013e3181889324] [Citation(s) in RCA: 190] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The purpose of this investigation was to examine the impact of training on the power-, force-, and velocity-time curves of the countermovement jump (CMJ) through both cross-sectional and longitudinal comparisons. The most novel aspect of this study was the analysis of these curves for the entire movement at a sampling frequency of 386-506 Hz averaged across 30 subjects. Thirty subjects, all men, participated in this investigation and included 12 athletes and 18 untrained men. Two major comparisons were conducted: 1) an acute, cross-sectional examination comparing experienced jumpers (jump height > 0.50 m; n = 12 men's athletes) with nonjumpers (jump height < 0.50 m; n = 14 untrained men), and 2) a longitudinal examination comparing performance before and after 12 weeks of power training (training group n = 10 untrained men; control group n = 8 untrained men). Data obtained from the baseline testing session of 14 subjects involved in the longitudinal study were used for the cross-sectional examination to represent the nonjumper group. The cross-sectional examination revealed significant (p <or= 0.05) differences between jumpers and nonjumpers in peak performance variables (i.e., peak power, force, velocity, displacement) as well as over a range of time points throughout the power-, force-, velocity-, and displacement-time curves of the CMJ. Similar results were observed in the longitudinal examination, with power training eliciting significant changes to peak performance variables as well as significant changes to the power-, force-, velocity-, and displacement-time curves over a range of time points throughout the CMJ. This study illustrates that training status not only influences the peak performance variables of the countermovement jump but also impacts the shape of the power-, force-, velocity-, and displacement-time curves throughout the movement. Because analysis of peak performance variables offers little insight into how adaptations have occurred after training, examination of the changes to the power-, force-, velocity-, and/or displacement-time curves offers a simple yet powerful monitoring technique that practitioners can use to gain insight into the precise nature and timing of adaptations to training.
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Affiliation(s)
- Prue Cormie
- School of Exercise, Biomedical and Health Sciences, Edith Cowan University, Perth, Australia.
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McBride JM, McCaulley GO, Cormie P, Nuzzo JL, Cavill MJ, Triplett NT. Comparison of Methods to Quantify Volume During Resistance Exercise. J Strength Cond Res 2009; 23:106-10. [DOI: 10.1519/jsc.0b013e31818efdfe] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Cormie P, McBride JM, McCaulley GO. The influence of body mass on calculation of power during lower-body resistance exercises. J Strength Cond Res 2008; 21:1042-9. [PMID: 18076268 DOI: 10.1519/r-21636.1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The objective of this investigation was to examine the influence of body mass in the calculation of power and the subsequent effect on the load-power relationship in the jump squat, squat, and power clean. Twelve Division I male athletes were evaluated on their performance across various intensities in all the 3 lifts. Power output was calculated using 3 separate techniques: (a) including the contribution of body mass in force output (IBM), (b) including the contribution of the mass of body less the mass of the shanks and feet in force output (IBMS), and (c) excluding the contribution of body mass in force output (EBM). Peak power, peak power relative to body mass, and peak force calculated using EBM were significantly (p < or = 0.05) lower than outputs calculated with IBM and IBMS. The load that maximized power output was unchanged between the 3 techniques in the jump squat (0% 1 repetition maximum [1RM]) and power clean (80% 1RM) but was shifted from 56% (IBM and IBMS) to 71% 1RM (EBM) in the squat. Across all 3 movements, the shape of the load-power curve was affected when derived via the EBM method as a result of the underrepresentation of power output at light loads. This was due to the majority of the load being neglected when the mass of the body was removed from the system mass used in the calculation of force. This study indicates that not only is the actual power output significantly lower when body mass is excluded from the force output of a lower body movement, but the load-power relationship is altered as well. Therefore, it is imperative that the mass of the individual being tested is incorporated into the calculation of force used to determine power output during lower-body movements.
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Affiliation(s)
- Prue Cormie
- School of Exercise, Biomedical and Health Sciences, Edith Cowan University, Perth, Western Australia
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Dumke CL, McBride JM, Nieman DC, Gowin WD, Utter AC, McAnulty SR. Effect of duration and exogenous carbohydrate on gross efficiency during cycling. J Strength Cond Res 2008; 21:1214-9. [PMID: 18076275 DOI: 10.1519/r-22396.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The purpose of this investigation was to determine the effects of 2.5 hours of cycling with and without carbohydrate supplementation on gross efficiency (GE). Trained cyclists (N = 15) were tested for V(.-)O2max (53.6 + 2.2 ml x kg(-1) x min(-1)) and lactate threshold during incremental tests to exhaustion. On 2 separate visits, cyclists performed 2.5 hours of cycling on an indoor trainer. A carbohydrate (C) or placebo (P) beverage was randomly provided and counterbalanced for each of the trials. Gross efficiency, cycling economy, power output, V(.-)O2, lactate, and blood glucose were measured every 20 minutes during the 2.5-hour ride. Muscle glycogen was measured immediately before and after the ride from the vastus lateralis. Results indicated that power output and V(.-)O2 decreased over time (p < 0.05) but were not different between trials. Relative GE and cycling economy during C were greater than P at 40 and 150 minutes (p < 0.05). Blood glucose significantly decreased in P and was lower than C at all time points (p < 0.05). Respiratory exchange ratio decreased over time in both trials, with a significant treatment effect at 40 and 150 minutes (p < 0.05). Muscle glycogen decreased by 65% during both conditions (p < 0.05) but demonstrated no treatment effect. We conclude that carbohydrate supplementation during 2.5 hours of cycling attenuated the decrease in GE possibly by maintaining blood glucose levels. This suggests that the positive effect of carbohydrate supplementation on endurance performance may be through the maintenance of metabolic efficiency.
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Affiliation(s)
- Charles L Dumke
- Human Performance Laboratory, Fisher Hamilton/Nycom Laboratory, and Neuromuscular Laboratory, Appalachian State University, Boone, North Carolina 28608, USA.
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Winchester JB, McBride JM, Maher MA, Mikat RP, Allen BK, Kline DE, McGuigan MR. Eight Weeks of Ballistic Exercise Improves Power Independently of Changes in Strength and Muscle Fiber Type Expression. J Strength Cond Res 2008; 22:1728-34. [DOI: 10.1519/jsc.0b013e3181821abb] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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McBride JM, McCaulley GO, Cormie P. Influence of preactivity and eccentric muscle activity on concentric performance during vertical jumping. J Strength Cond Res 2008; 22:750-7. [PMID: 18438244 DOI: 10.1519/jsc.0b013e31816a83ef] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The purpose of this investigation was to observe the influence of increasing amounts of preactivity and eccentric muscle activity imposed by three different jump types on concentric vertical jumping performance. Sixteen athletes involved in jumping-related sports at Appalachian State University, which is a Division IA school, performed a static jump (SJ), counter-movement jump (CMJ), and drop jump (DJ). Force, power, velocity, and jump height were measured during each jump type. In addition, muscle activity was measured from two agonist muscles (vastus lateralis, vastus medialis) and one antagonist muscle (biceps femoris). Preactivity and eccentric phase muscle activity of the agonist muscles (average integrated electromyography) was significantly (p < or = 0.05) higher during the DJ (preactivity, 0.2 +/- 0.11 mV; eccentric phase, 1.00 +/- 0.36 mV) in comparison with the CMJ (preactivity, 0.11 +/- 0.10 mV; eccentric phase, 0.45 +/- 0.17 mV). Peak concentric force was highest during the DJ and was significantly different among all three jump types (SJ, CMJ, DJ). Maximal jump height was significantly higher during the DJ (0.41 +/- 0.05 m) and CMJ (0.40 +/- 0.06 m) compared with the SJ (0.37 +/- 0.07 m). However, no significant difference in jump height existed between the CMJ and DJ. A positive energy balance, as assessed by force-displacement curves during the eccentric and concentric phases, was observed during the CMJ, and a negative energy balance was observed during the DJ. The data from this investigation indicate that a significant increase in concentric vertical jump performance is associated with increased levels of preactivity and eccentric phase muscle activity (SJ to CMJ). However, higher eccentric loading (CMJ to DJ) leads to a negative energy balance during the eccentric phase, which may relate to a non-significant increase in vertical jump height, even with coincidental increases in peak concentric force. Practitioners may want to focus on improving eccentric phase muscle activity through the use of plyometrics to improve overall jumping performance in athletes.
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Affiliation(s)
- Jeffrey M McBride
- Department of Health, Leisure and Exercise Science, Appalachian State University, Boone, North Carolina, USA.
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Hudson MB, Hosick PA, McCaulley GO, Schrieber L, Wrieden J, McAnulty SR, Triplett NT, McBride JM, Quindry JC. The effect of resistance exercise on humoral markers of oxidative stress. Med Sci Sports Exerc 2008; 40:542-8. [PMID: 18379219 DOI: 10.1249/mss.0b013e31815daf89] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
UNLABELLED Previous research attempts to identify an oxidative stress response to acute resistance exercise have yielded mixed results. Inconsistencies in the current literature base probably reflect study-to-study variance in resistance exercise protocols; where high volume and short recovery elicit the most identifiable oxidative stress response. PURPOSE This study examined the effect of resistance exercise intensity on blood oxidative stress. METHODS To elicit a blood oxidative stress, 10 subjects undertook two different back squat protocols: 1) a hypertrophy protocol of four sets, 10 repetitions with 90 s of rest at 75% one-repetition max (1RM); and 2) a strength protocol of 11 sets, three repetitions with 5 min of rest at 90% 1RM. The resistance exercise protocols were standardized for total volume and completed in a randomized crossover fashion with 1 wk between trials. Blood drawn before (PRE), immediately following exercise (IP), and 60 min following exercise (60POST) was analyzed for markers of oxidative stress and damage. RESULTS In response to both hypertrophy and strength exercise protein carbonyls were significantly elevated IP and 60POST while plasma lipid hydroperoxides were not. Following the hypertrophy protocol, trolox equivalent antioxidant capacity was elevated IP while urate lower than baseline. At the 60POST time point plasma ferric reducing ability of plasma was elevated following the hypertrophy protocol. Based on protein carbonyl data, a similar oxidative stress was incurred following both hypertrophy and strength protocols. CONCLUSION Normalization for time of blood draw following the two protocols indicates that the magnitude of blood oxidative protein damage was identical between the protocols. These findings demonstrate that both resistance exercise protocols elicited a blood oxidative stress in a time-dependent fashion.
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Affiliation(s)
- Matthew B Hudson
- Department of Health, Leisure and Exercise Science, Appalachian State University, Boone, NC 28607, USA
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Winchester JB, Porter JM, McBride JM, Nelson AG. Changes in Bar Path Kinematics and Kinetics Through Use of Summary Feedback in Power Snatch Training. Med Sci Sports Exerc 2008. [DOI: 10.1249/01.mss.0000322383.72996.e7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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