Factors contributing to lower metabolic demand of eccentric compared with concentric cycling

This study compared muscle-tendon behavior, muscle oxygenation, and muscle activity between eccentric and concentric cycling exercise at the same work output to investigate why metabolic demand is lower during eccentric cycling than with concentric cycling. Eleven untrained men (27.1 ± 7.0 y) performed concentric cycling (CONC) and eccentric cycling (ECC) for 10 min (60 rpm) at 65% of the maximal concentric cycling power output (191 ± 45 W) 4 wk apart. During cycling, oxygen consumption (V̇o2), heart rate (HR), vastus lateralis (VL) tissue total hemoglobin (tHb), and oxygenation index (TOI) were recorded, and muscle-tendon behavior was assessed using ultrasonography. The surface electromyogram (EMG) was recorded from VL, vastus medialis (VM), rectus femoris (RF), and biceps femoris (BF) muscles, and cycling torque and knee joint angle during each revolution were also recorded. Average V̇o2 (−65 ± 7%) and HR (−35 ± 9%) were lower and average TOI was greater (16 ± 1%) during ECC than CONC, but tHb was similar between bouts. Positive and negative cycling peak crank torques were greater (32 ± 21 and 48 ± 24%, respectively) during ECC than CONC, but muscle-tendon unit and fascicle and tendinous tissue length changes during pedal revolutions were similar between CONC and ECC. VL, VM, RF, and BF peak EMG amplitudes were smaller (24 ± 15, 22 ± 18, 16 ± 17, and 18 ± 9%, respectively) during ECC than CONC. These results suggest that the lower metabolic cost of eccentric compared with concentric cycling was due mainly to a lower level of muscle activation per torque output. NEW & NOTEWORTHY This study shows that lower oxygen consumption of eccentric compared with concentric cycling at the same workload is explained by lower muscle activity of agonist and antagonist muscles during eccentric compared with during concentric cycling.

Download Full-text

Differences of Thigh Muscle Activation During Various Squat Exercise on Stable and Unstable Surfaces

Exercise Science ◽

10.15857/ksep.2021.30.3.387 ◽

2021 ◽

Vol 30 (3) ◽

pp. 387-395

Author(s):

Soojin Kim ◽

Joo-Hyun Lee ◽

Jihye Heo ◽

Eunwook Chang

Keyword(s):

Muscle Activity ◽

Repeated Measures ◽

Muscle Activation ◽

Vastus Lateralis ◽

Rectus Femoris ◽

Biceps Femoris ◽

Quadriceps Muscle ◽

Thigh Muscle ◽

Unstable Surface ◽

Co Activation

PURPOSE: The purpose of this study was to compare thigh muscle activities and muscle co-activation when performing squats, wall squats, and Spanish squats on stable and unstable ground.METHODS: Twenty-two healthy male subjects (age: 22.50±2.70 years, height: 178.72±6.04 cm, mass: 76.50±6.80 kg, body mass index: 24.00±2.10 kg/m2, and Godin activity questionnaire: 56.30±24.10) voluntarily participated in the study. All of the participants performed three different squat exercises on the floor and the BOSU ball with an electromyograph attached to each participant’s quadriceps (rectus femoris, RF; vastus lateralis, VL; and vastus medialis, VM) and hamstrings (biceps femoris, BF; semitendinosus, ST; and semimembranosus, SM). Repeated measures of analysis of variance were utilized to compare muscle activity during the three squats exercises by floor type.RESULTS: RF (p<.001, η2=.689), VL (p<.001, η2=.622), and VM (p=.002, η2=.375) showed significant differences between exercises. Spanish squats yielded greater BF activity than did wall squats (p=.018, η2=.269). ST yielded greater muscle activity with the BOSU ball than on the floor (p=.018, η2=.269). Finally, there was a significant ground exercise interaction effect on the co-activation, showing greater muscle co-activation with Spanish squats on the BOSU ball compared to squats, squats on the BOSU ball, and wall squat on the BOSU ball.CONCLUSIONS: The findings of this study indicate that Spanish squats could be an effective exercise option for the facilitation of RF, VL, VM, and BF muscle activation. In particular, performing Spanish squats on an unstable surface could be useful for patients who need to improve their quadriceps muscle activation.

Download Full-text

A Neuromuscular and Metabolic Comparison between Forward and Reverse Pedaling

Journal of Applied Biomechanics ◽

10.1123/jab.14.4.401 ◽

1998 ◽

Vol 14 (4) ◽

pp. 401-411 ◽

Cited By ~ 11

Author(s):

Eadric Bressel ◽

Gary D. Heise ◽

Greg Bachman

Keyword(s):

Oxygen Consumption ◽

Muscle Activity ◽

Tibialis Anterior ◽

Muscle Activation ◽

Knee Extensor ◽

Rectus Femoris ◽

Biceps Femoris ◽

Half Cycle ◽

Physically Active ◽

Crank Angle

The purpose of this study was to determine how muscle activity and oxygen consumption are influenced by reverse pedaling (RP) compared to forward pedaling (FP). Seventeen physically active males performed FP and RP at an external workrate of 157 W (80 rpm) while EMG data were collected from five muscles: rectus femoris (RF), biceps femoris (BF), gastrocnemius (GN), tibialis anterior (TA), and vastus medialis (VM). Oxygen consumption (V̇O2 L·min-1) data were collected. On-time durations and EMG amplitudes were quantified for each half-cycle (first 180° and second 180° of crank angle). V̇O2 was similar between pedaling conditions while muscles RF and BF exhibited phasic shifts in response to RP with no amplitude change. VM showed an increase and GN displayed a decrease in EMG amplitude from FP to RP. The phasic shifts in muscle activation seen in RP, particularly in RF and BF, may alter the sequence of the knee extensor–hip extensor joint moments during the first half-cycle of pedaling.

Download Full-text

Quadriceps and hamstrings coactivation in exercises used in prevention and rehabilitation of hamstring strain injury in young soccer players

10.1101/574210 ◽

2019 ◽

Author(s):

Gonzalo Torres ◽

David Chorro ◽

Archit Navandar ◽

Javier Rueda ◽

Luís Fernández ◽

...

Keyword(s):

Muscle Activation ◽

Vastus Lateralis ◽

Rectus Femoris ◽

Biceps Femoris ◽

Activation Pattern ◽

Male Youth ◽

Maximum Voluntary Isometric Contraction ◽

Hamstring Strain ◽

Exercise Muscle ◽

Injury Recovery

AbstractThis study aimed to study the co-activation of hamstring-quadriceps muscles during submaximal strength exercises without the use of maximum voluntary isometric contraction testing and compare (i) the inter-limb differences in muscle activation, (ii) the intra-muscular group activation pattern, and (iii) the activation during different phases of the exercise. Muscle activation was recorded by surface electromyography of 19 elite male youth players. Participants performed five repetitions of the Bulgarian squat, lunge and the squat with an external load of 10 kg. Electrical activity was recorded for the rectus femoris, vastus medialis, vastus lateralis, biceps femoris and semitendinosus. No significant inter-limb differences were found (F1, 13=619; p=0.82; partial η2=0.045). Significant differences were found in the muscle activation between different muscles within the muscle group (quadriceps and hamstrings) for each of the exercises: Bulgarian squat (F1,18=331: p<0.001; partial η2=0.80), lunge (F4,72=114.5; p<0.001; partial η2=0.86) and squat (F1,16=247.31; p<0.001; partial η2=0.93).Differences were found between the concentric, isometric and eccentric phases of each of the exercises (F2, 26=52.27; p=0.02; partial η2=0.80). The existence of an activation pattern of each of the muscles in the three proposed exercises could be used for muscle assessment and as a tool for injury recovery.

Download Full-text

Characterization of kinesiological patterns of the frontal kick, mae-geri, in karate experts and non-karate practitioners

Revista de Artes Marciales Asiáticas ◽

10.18002/rama.v9i1.1163 ◽

2014 ◽

Vol 9 (1) ◽

pp. 20 ◽

Cited By ~ 3

Author(s):

António M. VencesBrito ◽

Marco A. Colaço Branco ◽

Renato M. Cordeiro Fernandes ◽

Mário A. Rodrigues Ferreira ◽

Orlando J. S. M. Fernandes ◽

...

Keyword(s):

Muscle Activity ◽

Vastus Lateralis ◽

Plantar Flexion ◽

Neuromuscular Control ◽

Rectus Femoris ◽

Biceps Femoris ◽

Knee Extension ◽

Maximum Speed ◽

Ballistic Performance ◽

The Impact

Presently, coaches and researchers need to have a better comprehension of the kinesiological parameters that should be an important tool to support teaching methodologies and to improve skills performance in sports. The aim of this study was to (i) identify the kinematic and neuromuscular control patterns of the front kick (mae-geri) to a fixed target performed by 14 experienced karate practitioners, and (ii) compare it with the execution of 16 participants without any karate experience, allowing the use of those references in the analysis of the training and learning process. Results showed that the kinematic and neuromuscular activity during the kick performance occurs within 600 ms. Muscle activity and kinematic analysis demonstrated a sequence of activation bracing a proximal-to-distal direction, with the muscles presenting two distinct periods of activity (1, 2), where the karateka group has a greater intensity of activation – root mean square (RMS) and electromyography (EMG) peak – in the first period on Rectus Femoris (RF1) and Vastus Lateralis (VL1) and a lower duration of co-contraction in both periods on Rectus Femoris-Biceps Femoris and Vastus Lateralis-Biceps Femoris (RF-BF; VL-BF). In the skill performance, the hip flexion, the knee extension and the ankle plantar flexion movements were executed with smaller difference in the range of action (ROA) in the karateka group, reflecting different positions of the segments. In conclusion, it was observed a general kinesiological pattern, which was similar in karateka and non-karateka practitioners. However, in the karateka group, the training induces a specialization in the muscle activity reflected in EMG and kinematic data, which leads to a better ballistic performance in the execution of the mae-geri kick, associated with a maximum speed of the distal segments, reached closer to the impact moment, possibly representing more power in the contact.

Download Full-text

Electromyographic responses to Nordic curl and prone leg curl exercises in football players

Physical Education of Students ◽

10.15561/20755279.2021.0505 ◽

2021 ◽

Vol 25 (5) ◽

pp. 288-298

Author(s):

Murat Çilli ◽

Merve N. Yasar ◽

Onur Çakir

Keyword(s):

Muscle Activity ◽

Muscle Activation ◽

Total Duration ◽

Rectus Femoris ◽

Random Order ◽

Biceps Femoris ◽

Activation Rate ◽

Significant Difference ◽

Activation Rates ◽

Short Time

Background and Study Aim. The aim of this study is to examine the electromyographic responses to Nordic curl and prone leg curl exercises, having two different mechanics. Material and Methods. The athletes performed the prone leg curl and Nordic curl exercises in random order, 6 repetitions each. Electromyographic data of semimemranosus, semitendinosus, biceps femoris and rectus femoris muscles were recorded by 8-channel electromyography in order to examine the muscle responses to exercises. Total duration of exercise, cumulative integrated electromyographic values and muscle activation rates in 5 different intensity zones determined according to MVC% values have been compared. Results. Prone leg curl exercise occurred in less time than Nordic curl exercise. According to the cumulative integrated electromyography data results, all muscles showed similar muscle activation in both exercises. Comparing the muscle activation rates in the five intensity zones, more muscle activity was observed for Nordic curl exercise in the first intensity zone, while prone leg curl exercise was more active in the third and fourth zones. During the prone leg curl exercise, the muscle activation rate of the dominant leg is higher in the first intensity zone, whereas the non-dominant leg in the fourth intensity zone has a higher muscle activation. During the Nordic curl exercise, the muscle activation rates of the dominant leg in the first and fifth intensity zones are higher, whereas the nondominant leg in the fourth intensity zone is higher. Conclusions. Prone leg curl exercises can be preferred in order to stimulate high muscle activation in a short time. Comparing the two exercises there was no significant difference in muscle activity in dominant and nondominant legs.

Download Full-text

Evaluation of the Lower Limb Muscles’ Electromyographic Activity during the Leg Press Exercise and Its Variants: A Systematic Review

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph17134626 ◽

2020 ◽

Vol 17 (13) ◽

pp. 4626

Author(s):

Isabel Martín-Fuentes ◽

José M. Oliva-Lozano ◽

José M. Muyor

Keyword(s):

Muscle Activation ◽

Vastus Lateralis ◽

Muscular Activity ◽

Rectus Femoris ◽

Biceps Femoris ◽

Quadriceps Muscle ◽

Electromyographic Activity ◽

Full Extension ◽

Cross Sectional ◽

Leg Press

The aim of this study was to analyze the literature on muscle activation measured by surface electromyography (sEMG) of the muscles recruited when performing the leg press exercise and its variants. The Preferred Reporting Items of Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed to report this review. The search was carried out using the PubMed, Scopus, and Web of Science electronic databases. The articles selected met the following inclusion criteria: (a) a cross-sectional or longitudinal study design; (b) neuromuscular activation assessed during the leg press exercise, or its variants; (c) muscle activation data collected using sEMG; and (d) study samples comprising healthy and trained participants. The main findings indicate that the leg press exercise elicited the greatest sEMG activity from the quadriceps muscle complex, which was shown to be greater as the knee flexion angle increased. In conclusion, (1) the vastus lateralis and vastus medialis elicited the greatest muscle activation during the leg press exercise, followed closely by the rectus femoris; (2) the biceps femoris and the gastrocnemius medialis showed greater muscular activity as the knee reached full extension, whereas the vastus lateralis and medialis, the rectus femoris, and the tibialis anterior showed a decreasing muscular activity pattern as the knee reached full extension; (3) evidence on the influence of kinematics modifications over sEMG during leg press variants is still not compelling as very few studies match their findings.

Download Full-text

Altering muscle activity in the lower extremities by bipedal landing with different drop tasks and shoes

Isokinetics and Exercise Science ◽

10.3233/ies-210212 ◽

2021 ◽

pp. 1-11

Author(s):

Yang Yang ◽

Changxiao Yu ◽

Chenhao Yang ◽

Liqin Deng ◽

Weijie Fu

Keyword(s):

Lower Extremity ◽

Muscle Activation ◽

Vastus Lateralis ◽

Movement Control ◽

Rectus Femoris ◽

Biceps Femoris ◽

The Body ◽

Basketball Players ◽

Lower Extremity Muscle ◽

Body Tissues

BACKGROUND: The ability of the lower-extremity muscle activation directly affects the performance and in turn interacts with the loading conditions of the muscle itself. However, systematic information concerning the characteristics of lower-extremity muscle during landings is lacking. In particular, the landing height and shoes are also important factors based on the actual situation, which could further contribute to understanding the neuromuscular activity and how biochemical response of the body tissues to double-leg drop landings. OBJECTIVE: The study was to investigate the effects of landing tasks on the activation of lower-extremity muscles and explore the relationship among movement control, landing heights, shoe cushioning, and muscle activities. METHODS: Twelve male basketball players were recruited to perform drop jump (DJ) and passive landing (PL) from three heights (30, 45, and 60 cm) while wearing highly-cushioned basketball shoes (HC) and less-cushioned control shoes (LC). EMG electrodes were used to record the activities of the target muscles (rectus femoris, vastus lateralis, biceps femoris, tibialis anterior, and lateral gastrocnemius) during the landing tasks. RESULTS: Pre- and post-activation activity of the lower-extremity muscles significantly decreased during PL compared with those during DJ (p< 0.05). No significant shoe effects on the characteristics of muscle activation and coactivation during DJ movements were observed. However, the participants wearing LC showed significantly higher muscle post-activation (p< 0.05) at the three drop heights during PL compared with those wearing HC. Coactivation of the ankle muscles was higher in LC than in HC during 30-cm PL (p< 0.05). CONCLUSIONS: The activation patterns of lower-extremity muscles can be significantly influenced by landing types. Highly-cushioned basketball shoes would help reduce the risk of injuries by appropriately tuning the muscles during the PL.

Download Full-text

Metabolic Demand and Muscle Activation during Different Forms of Bodyweight Supported Locomotion in Men with Incomplete SCI

BioMed Research International ◽

10.1155/2014/632765 ◽

2014 ◽

Vol 2014 ◽

pp. 1-10 ◽

Cited By ~ 12

Author(s):

Alyssa M. Fenuta ◽

Audrey L. Hicks

Keyword(s):

Body Weight ◽

Muscle Activation ◽

Rectus Femoris ◽

Biceps Femoris ◽

Medial Gastrocnemius ◽

Locomotor Training ◽

Metabolic Demand ◽

Metabolic Equivalents ◽

Weight Support ◽

Cord Injury

Body weight supported locomotor training uses neuroplasticity principles to improve recovery following a spinal cord injury (SCI). Steady state locomotion using the same body weight support (BWS) percent was compared in 7 males (42.6±4.29 years) with incomplete SCI and matched (gender, age) noninjured controls (42.7±5.4 years) using the Lokomat, Manual Treadmill, and ZeroG. The VO2000, Polar Heart Rate (HR) Monitor, and lower limb electromyography (EMG) electrodes were worn during the 2-minute sessions. Oxygen uptake (VO2) and HR were expressed as percentage of peak values obtained using progressive arm ergometry; VO2was also expressed relative to resting metabolic equivalents (METS). Filtered EMG signals from tibialis anterior (TA), rectus femoris (RF), biceps femoris (BF), and medial gastrocnemius (MG) were normalized to ZeroG stepping. The Lokomat required 30% of VO2peak (2METS) compared to ~54% (3METS) for Manual Treadmill and ZeroG sessions. HR was 67% of peak during Lokomat sessions compared to ~83% for Manual Treadmill and ZeroG. Muscle activation was higher in treadmill conditions compared to the ZeroG primarily due to increased BF activity. At the same level of BWS, locomotion using the Manual Treadmill or the ZeroG is more aerobically demanding than the Lokomat. Treadmill modalities encourage greater hip extensor activation compared to overground locomotion.

Download Full-text

Electromyographic evaluation of the lower limbs of patients with Down syndrome in hippotherapy

Acta Scientiarum Health Sciences ◽

10.4025/actascihealthsci.v39i1.28868 ◽

2017 ◽

Vol 39 (1) ◽

pp. 17 ◽

Cited By ~ 3

Author(s):

Mariane Fernandes Ribeiro ◽

Ana Paula Espindula ◽

Alex Abadio Ferreira ◽

Luciane Aparecida Pascucci Sande de Souza ◽

Vicente De Paula Antunes Teixeira

Keyword(s):

Down Syndrome ◽

Muscle Activation ◽

Motor Behavior ◽

Vastus Lateralis ◽

Rectus Femoris ◽

Gluteus Medius ◽

Biceps Femoris ◽

Functional Results ◽

Lower Limbs ◽

Tensor Fasciae Latae

Hippotherapy is a therapeutic method that uses the horse’s movement to achieve functional results in practitioners with Down syndrome (DS), who present motor and neurophysiological changes that affect the musculoskeletal system. Evaluating the motor behavior related to the control and the improvement of muscle activation in practitioners with Down syndrome subjected to hippotherapy. 10 practitioners were divided into two groups: Down Group (DG) – practitioners with DS, and Healthy Group (HG) – practitioners with no physical impairment. The muscles gluteus medius, tensor fasciae latae, rectus femoris, vastus medialis, vastus lateralis, biceps femoris, tibialis anterior and gastrocnemius were evaluated by electromyography using gross RMS values, which correspond to muscle activation; the evaluations were performed on the 1st and 10th hippotherapy sessions (frequency: once a week), and after 2 months interval without treatment, they were performed on the 1st and 10th hippotherapy sessions (frequency: twice a week). It was noted that activation of the studied muscles increased with the passing of sessions, regardless the weekly frequency of attendance; however, the period without treatment resulted in reduction of this effect. Practitioners with DS presented satisfactory changes in muscle activation pattern, in learning and in motor behavior during hippotherapy sessions.

Download Full-text

Leg Muscle Activity and Perception of Effort before and after Four Short Sessions of Submaximal Eccentric Cycling

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph17217702 ◽

2020 ◽

Vol 17 (21) ◽

pp. 7702

Author(s):

Pierre Clos ◽

Romuald Lepers

Keyword(s):

Muscle Activity ◽

Peak Power ◽

Vastus Lateralis ◽

Rectus Femoris ◽

Biceps Femoris ◽

Peak Power Output ◽

Leg Muscles ◽

Perception Of Effort ◽

Before And After ◽

Power Outputs

Background: This study tested muscle activity (EMG) and perception of effort in eccentric (ECC) and concentric (CON) cycling before and after four sessions of both. Methods: Twelve volunteers naïve to ECC cycling attended the laboratory six times. On day 1, they performed a CON cycling peak power output (PPO) test. They then carried-out four sessions comprising two sets of 1 to 1.5-min cycling bouts at 5 intensities (30, 45, 60, 75, and 90% PPO) in ECC and CON cycling. On day 2 and day 6 (two weeks apart), EMG root mean square of the vastus lateralis (VL), rectus femoris (RF), biceps femoris (BF), and soleus (SOL) muscles, was averaged from 15 to 30 s within each 1-min bout and perception of effort was asked after 45 s. Results: Before the four cycling sessions, while VL EMG was lower in ECC than CON cycling, most variables were not different. Afterwards, ECC cycling exhibited lower RF EMG at 75 and 90% PPO (all p < 0.02), lower VL and BF EMG at all exercise intensities (all p < 0.02), and inferior SOL EMG (all p < 0.04) except at 45% PPO (p = 0.07). Perception of effort was lower in ECC cycling at all exercise intensities (all p < 0.03) but 60% PPO (p = 0.11). Conclusions: After four short sessions of ECC cycling, the activity of four leg muscles and perception of effort became lower in ECC than in CON cycling at most of five power outputs, while they were similar before.

Download Full-text