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Electromyographic analysis of muscle activation during pull-up variations
Abstract
This study sought to identify any differences in peak muscle activation (EMGPEAK) or average rectified variable muscle activation (EMGARV) during supinated grip, pronated grip, neutral grip and rope pull-up exercises. Nineteen strength trained males (24.9 ± 5 y; 1.78 ± 0.74 m; 81.3 ± 11.3 kg; 22.7 ± 2.5 kg·m¯²) volunteered to participate in the study. Surface electromyography (EMG) was collected from eight shoulder-arm-forearm complex muscles. All muscle activation was expressed as a percentage of maximum voluntary isometric contraction (%MVIC). Over a full repetition, the pronated grip resulted in significantly greater EMGPEAK (60.1 ± 22.5 vs. 37.1 ± 13.1%MVIC; P = .004; Effect Size [ES; Cohen’s d] = 1.19) and EMGARV (48.0 ± 21.2 vs. 27.4 ± 10.7%MVIC; P = .001; ES = 1.29) of the middle trapezius when compared to the neutral grip pull-up. The concentric phases of each pull-up variation resulted in significantly greater EMGARV of the brachioradialis, biceps brachii, and pectoralis major in comparison to the eccentric phases (P = < 0.01). Results indicate that EMGPEAK and EMGARV of the shoulder-arm-forearm complex during complete repetitions of pull-up variants are similar despite varying hand orientations; however, differences exist between concentric and eccentric phases of each pull-up.
... During the pull-up exercise, there are substantial differences in muscle activation when the width between hands or the forearm orientation (intended according to supinated or pronated pull-ups) changes. In fact, differences are present both for a smaller bending of the elbow and for the different working planes of the humerus [1,11,22]. Urbanczyk et al. [22] reported that during wide pull-ups the latissimus dorsi was more active than in pronated shoulder width pull-ups (in which biceps brachii and brachialis activation was prevalent) and supinated pull-ups (in which rotator cuff activation was prevalent). Lusk et al. [11] found that wide-width lat pull-down did not significantly influence the latissimus dorsi activation, which seems to be more active with a pronated than a supinated grip, although analysed during lat pull-down exercise (performed using a lat machine). ...
... Lusk et al. [11] found that wide-width lat pull-down did not significantly influence the latissimus dorsi activation, which seems to be more active with a pronated than a supinated grip, although analysed during lat pull-down exercise (performed using a lat machine). Further, Dickie et al. [1] examined the electromyographic muscle activity during different types of pull-ups: prone, supine, and neutral. The authors observed that middle trapezius activity was higher during pronated pull-ups (compared to neutral) [1]. ...
... Further, Dickie et al. [1] examined the electromyographic muscle activity during different types of pull-ups: prone, supine, and neutral. The authors observed that middle trapezius activity was higher during pronated pull-ups (compared to neutral) [1]. Moreover, muscle activation was similar during all types of pullups, while different activation was noted between eccentric and concentric phases [1]. ...
Study aim : The aim of this study is to assess whether a closed (CG) or open grip (OC) can influence the maximum number of repetitions during the pull-up test to exhaustion.
Material and methods : Ninety-five physically active males (age 23.5 ± 6.2 years, body mass 69 ± 7.9 kg, height 174.0 ± 6.4 cm, BMI 22.9 ± 2.2) randomly performed the pull-up test to exhaustion twice, once for each type of grip, one week apart.
Results : No significant difference (p = 0.092) was found between the maximum number of repetitions performed with the OG (14.2 ± 5.7) or the CG (13.9 ± 5.9). Spearman’s correlation showed no significant association between participants’ body mass and the number of repetitions (r = 0.128, p = 0.22 for OG; r = 0.157, p = 0.13 for CG).
Conclusions : According to our results, the grip is not relevant in the determination of the performance during a pull-up test to exhaustion. Thus, using one grip instead of another may be recommended independently of performance needs. Grip type may be adapted considering the practised sport, and specific athletic requirements, as well as individual preference.
... There is a lack of studies about the impact of the exercise technique in the PU performance. However, even small differences in grip width or hand position can affect muscle activation and mechanical variables (Dickie et al., 2017;Leslie & Comfort, 2013). Up until now, differences in PU muscle activation by change in hand orientation (supinated, pronated, neutral and rope grips) have been described (Dickie et al., 2017;Leslie & Comfort, 2013). ...
... However, even small differences in grip width or hand position can affect muscle activation and mechanical variables (Dickie et al., 2017;Leslie & Comfort, 2013). Up until now, differences in PU muscle activation by change in hand orientation (supinated, pronated, neutral and rope grips) have been described (Dickie et al., 2017;Leslie & Comfort, 2013). The scapular kinematics and external forces in three PU techniques (supinated, narrow and wide pronated grips) have also been addressed (Prinold & Bull, 2016). ...
... Despite this, research has shown that load-velocity (L-V), F-V and P-V relationships are sensitive to interindividual differences, movement patterns and muscle groups used (Jaric, 2015;Soriano et al., 2017). Consequently, considering that slight biomechanical differences in the same exercise could produce variations in the F-V profile or EMG (Dickie et al., 2017), it is reasonable to expect that the width of the grip will also produce them during the PU exercise. In the available literature, most of the studies conducted in PU have used a free grip (FREE) without anatomical references (Dinunzio et al., 2019;Halet et al., 2009;Perez-Olea et al., 2018;Thomas et al., 2018), one has used BA grip width (Youdas et al., 2010) and others described an imprecise approach, such as "slightly wider than shoulder width or approximately 150% of the BA distance" (Munoz-Lopez et al., 2017;Sánchez-Moreno et al., 2020;Sanchez-Moreno et al., 2017). ...
Purpose: The objective of this study was to investigate the influence of the grip width on the power-force-velocity-profile, the maximal strength, and performance during a repetition to failure test in the pull-up exercise (PU). Method: Fourteen trained males performed an incremental loading and repetitions to failure test with the PU exercise using biacromial and free grip widths. Power-force-velocity relationship, 1RM, and repetitions completed were determined. Results: The mean grip width used by participants was 20.04% higher in the free grip width condition (p < .001). There were similar results in the 1RM (p = .954), repetitions to failure test (p = .117), and power-force-velocity profile (p > .05) in both grip width conditions. A stronger relationship was observed between 1RM and repetitions to failure test during the biacromial (R ² = 0.720; p < .001) with respect to the free grip width (R ² = 0.607; p = .002). Conclusion: Therefore, the choice of a free or a biacromial grip width does not affect the maximal strength, power-force-velocity relationship, nor the repetitions to failure during the PU exercise.
... Schick et al. (2010) examined the bench press exercise and found the medial deltoid has the highest activations and the pectoralis major the second highest, when this is compared to similar studies with similar aims the medial deltoid has nearly half the activation levels of the pectoralis major (Tillaar and Ettema, 2013). Dickie et al. (2017) shows larger activations for the biceps brachii compared to the latissimus dorsi for the chin up exercise where as Youdas et al. (2010) found the opposite and the same findings were found for the pull up exercise. However, the push up exercise showed less variability between studies for the pectoralis major, triceps brachii (Snarr andEsco, 2013, Cogley et al., 2005) and anterior deltoid (Snarr andEsco, 2013, Borreani et al., 2015). ...
... The primary exercises highlighted within this review were; bench press, chin up and pull up. The findings suggest that the prime movers during bench press are both the middle deltoid and pectoralis major (Schick et al., 2010, Tillaar andEttema, 2013) with the prime movers during the chin up and pull up being the biceps brachii and latissimus dorsi (Dickie et al., 2017, Youdas et al., 2010. Whilst during front crawl swimming the muscles highlighted within this review are the latissimus dorsi, pectoralis major, triceps brachii and deltoids (Martens et al., 2015b) with the middle deltoid being highlighted as the prime mover (Martens et al., 2015a, Martens et al., 2016. ...
... Most overlaps between front crawl swimming and bench press occurred during both the catch and push phase for the middle deltoid and the catch and pull phase for the pectoralis major. Research investigating the muscle activations of the pull up exercise found higher muscle activations for the biceps brachii compared to the latissimus dorsi (Dickie et al., 2017). On the contrary, Youdas et al. (2010) found higher muscle activations in the latissimus dorsi compared to the biceps brachii. ...
Swimming performance requires a whole body coordinated movement to elicit high propulsive forces with the majority of forces produced from the upper body musculature. The current academic literature highlights a range of dry-land resistance exercises that show moderate to strong correlations to swimming performance; however, association does not imply causation. Specificity states that adaptations are specific to the nature of the training stress applied and therefore it is important to highlight the dry-land resistance exercises improving swimming performance. The aim of this research study is to examine the specificity of dry-land resistance exercises to swimming performance. A systematic review of the impact of resistance training on front crawl swimming performance highlighted that low volume, high force, traditional resistance training programmes, showed positive improvement in swimming performance. Neuromuscular adaptations contribute to resistance training exercises improving swimming performance according to several research studies. A review of the specificity between front crawl swimming and dry-land resistance exercises using electromyography (EMG) data highlighted a series of similar prime movers (i.e. latissimus dorsi, pectoralis major, triceps brachii and deltoids) between a range of dry-land resistance exercises. A qualitative study of elite swimming strength and conditioning coaches identified the dry-land resistance exercises most commonly used and deemed most relevant by practitioners and coaches. The bench press and pull up were the two upper body dry-land resistance exercises that coaches ranked highest in terms of improving swimming performance. This prompted an investigation of the specificity of these dry-land resistance exercises to front crawl swimming using EMG data analysis. Following a series of pilot tests, 14 male national and international swimmers were recorded using 2D kinematic analysis to identify event cycles and EMG to investigate muscle activations. The specificity of front crawl swimming to bench press and pull up exercises were examined using temporal coordination , temporal muscle activation overlaps, Functional Data Analysis (FDA) Pearson pointwise correlations, Statistical Parametric Mapping (SPM) t-tests and Root Mean Square Difference (RMSD). The findings of this research show that while the key prime movers between the bench press and pull up exercises and front crawl swimming are similar, there is limited specificity. The results would also suggest that these exercises are applicable for the general preparation period but not for the specific competition period. The large variability within the data set makes findings difficult to interpret. Future research needs to focus on individual analysis of specificity, as the large variability does not make group analysis techniques representative of the high level of individual variability found within the data set. Greater specificity is required through the development of a coherent biomechanical model of specificity that describes joint angles, angular velocity, torque and muscle activations.
... The first is the magnitude of muscle activation in the prime movers (i.e. latissimus dorsi, biceps brachii, trapezius, deltoid, erector spinae, rectus abdominis, etc. Dickie, Faulkner, Barnes and Lark [10], Snarr [9]. Activating the main muscles used in the alternative pulling exercises to a similar extent as that of the pullup will result in maximal transference from the training program and exercises to the exercise of interest; the body weight pull-up. ...
... iliopsoas and rectus femoris) to a lesser extent as a Performing the lat-pulldown from a kneeling position would create the neutral hip position that is more consistent with the traditional pull-up (and assisted pull-up) exercise. Research has recently begun to investigate the muscle activity of the latpulldown when varying the hand grip width and technique Dickie [10]; Lusk, Hale and Russell [11], Signorile, Zink and Szwed [12], Sperandei, Barros, Silveira-Junior and Oliveira [13]. However, to the knowledge of the authors of this study, the activation magnitudes of the prime movers during alternative pulling exercises compared to that of the BW pull-up has yet to be explored. ...
... pronated, supinated, etc.) and movement techniques (e.g. behind the neck versus in front of the neck, PU with rings, kipping PU, etc.) for the PU and lat-pulldown exercises Andersen [15], Dickie [10], Lusk [11], Signorile [12], Snarr [8], Snarr [9], Sperandei [13], Youdas [22]. This made it difficult to compare current EMG data to that of previously published data, specifically with the k-LP variation. ...
... EMG data were normalized via the use of previously reported maximal voluntary isometric contraction and break test protocols for the LT, MF, GM, BF, and ST (4,7,8,20). The break test for the LT and MF was completed by having the participant lie prone with their forehead resting flat on the table and their hands behind their head. ...
... Our findings align directly with this literature as the concentric phase of the RDL, RH, and CP all resulted in greater muscle activation compared to their eccentric phases. Similar results have also been observed when comparing variations of the pull-up exercise (7). These similar findings are likely because concentric contractions, compared to eccentric contractions, require greater levels of force production, and subsequently display greater activation (9). ...
Hinge exercises are critical to building a balanced resistance training program in concert with 'knee-dominant' (e.g., squat, lunge) exercises. Biomechanical differences between various straight-legged hinge (SLH) exercises may alter muscle activation. For example, a Romanian deadlift (RDL) is a closed-chain SLH, while a reverse hyperextension (RH) is open-chain. Likewise, the RDL offers resistance via gravity while the cable pull-through (CP) offers redirected-resistance through a pulley. A deeper understanding of the potential impact of these biomechanical differences between these exercises may improve their application to specific goals. Participants completed repetition-maximum (RM) testing on the RDL, RH, and CP. On a follow-up visit, surface electromyography of the longissimus, multifidus, gluteus maximus, semitendinosus, and biceps femoris, muscles that contribute to lumbar/hip extension, was recorded. After a warm-up, participants completed maximal voluntary isometric contractions (MVICs) in each muscle. They then completed five repetitions of the RDL, RH, and CP at 50% of estimated one RM. Testing order was randomized. A one-way, repeated-measures ANOVA test was used in each muscle to compare activation (%MVIC) across the three exercises. Shifting from a gravity-(RDL) to a redirected-resistance (CP) SLH significantly decreased activation in the longissimus (-11.0%), multifidus (-14.1%), biceps femoris (-13.1%), and semitendinosus (-6.8%). Alternately, changing from a closed-(RDL) to an open-chain (RH) SLH significantly increased activation in the gluteus maximus (+19.5%), biceps femoris (+27.9%), and semitendinosus (+18.2). Alterations in the execution of a SLH can change muscle activation in lumbar/hip extensors.
... They found only one difference between these conditions with lower muscle activity of the middle trapezius while performing towel pull-ups compared to the traditional pull-up. In another study, Dickie et al. [4] compared muscle activity during pull-ups performed in the supinated grip, pronated grip, neutral grip and on ropes hanging over the bar, finding differences only between the concentric and eccentric phases of each pull-up. However, the research mentioned above has limited applicability to the specifics of climbing training. ...
... Depending on how they are attached, they can offer either a stable or unstable hang point, which modifies the exercise conditions to simulate exercises performed either on a stable or unstable surface. While the effectiveness of performing different types of exercises depending on the type of surface (unstable vs. stable) has been the subject of research conducted by various authors [1,2,8,10], to date few studies have investigated the effectiveness of pulling exercises on a stable or unstable suspension point [4,14]. Additionally, to our best knowledge no research has been conducted in the context of training climbers. ...
This study was designed to investigate whether there was a difference
in movement velocity, power and force, as well one repetition
maximum (1RM) when pulling up on fingerboards or portable
holds. Material and Methods. Sixteen male climbers volunteered
to participate in the study (height: 176.4 ± 7.0 cm; weight: 72.4 ±
± 11.2 kg; age: 37.0 ± 10.0 years). Subjects performed pull-ups in
the fingerboard (offering a stable suspension point) or portable
holds (with single-point suspension offering freedom to move in
different directions of the horizontal plane). Movement parameters
(power, force, velocity of pull-ups) as well as estimated 1RM were
recorded using a Gyko inertial sensor. The analyses revealed
that the maximum values of force, power and velocity of pull-ups were
not significantly different between both devices. However, values
for one maximum repetition were higher on the fingerboard than
on portable holds (p < 0.001, ƞ2 = 0.71). On the basis of
the study results we can assume that fingerboards (fixed in a stable
way) may be relevant in developing maximal strength in pull-ups
... In addition, group 2 (the supinated group) performed slightly better than then group 1 (the pronated group) due to the grip being more comfortable to the second group compared to the first (see Figure 2). The mechanics of a supinated pull-up grip of the forearm places greater muscle activation of the biceps brachii within the elbow flexors (Dickie et al., 2017). A pronated grip increases brachialis muscle more so than the brachi muscle, which lacks muscle activation compared to the bicep brachii (Dickie et al., 2017). ...
... The mechanics of a supinated pull-up grip of the forearm places greater muscle activation of the biceps brachii within the elbow flexors (Dickie et al., 2017). A pronated grip increases brachialis muscle more so than the brachi muscle, which lacks muscle activation compared to the bicep brachii (Dickie et al., 2017). Interesting to note is that for the pre and posttest the neutral grip used increases brachioradialis activation (Floyd, 2012). ...
... 6 Surface electromyography (EMG) can measure relative magnitude of muscle contractions, but technical limitations in accessing the deeper rotator cuff muscles where injuries are most common 12,13 necessitates the use of musculoskeletal modeling to quantify joint and muscle biomechanics. There are few instances of electromyography derived kinematic analyses being applied to pull-ups 4, [14][15][16] and only one previous study has utilized an inverse dynamics modeling approach. 17 The aim of this study was to quantify, with musculoskeletal modeling, loading of key upper limb and torso muscles during several pull-up variants; to examine the effect of different kinematic strategies on muscle recruitment; and to highlight potential injury risks in concentric loading of vulnerable structures in these tasks. ...
... 17 Other studies have measured EMG during pull-up techniques with hand-grip variations and can be compared to model predictions of muscle force and recruitment predicted here. 4,[14][15][16] Normalized, modeled muscle force values were on average lower than normalized EMG measurements from literature but have similar trends. EMG muscle activations reported by Dinunzio et al 15 for the front pull-up and Runciman 17 for the reverse pull-up indicate latissimus dorsi as the most active muscle during the pull-up movement, with pectoralis major appearing significantly less important. ...
Heavily loaded overhead training tasks, such as pull‐ups are an effective strength training and rehabilitation exercise requiring high muscle forces maintained over a large range of motion. This study used experiments and computational modelling to examine loading patterns during three different pull‐up variants and highlighted risks to vulnerable musculoskeletal structures. Optical motion tracking and a force platform captured kinematics and kinetics of 11 male subjects with no history of shoulder pathology, during performance of three pull‐up variants – pronated front grip, pronated wide grip, and supinated reverse grip. UK National Shoulder model (UKNSM) simulated biomechanics of the shoulder girdle. Muscle forces and activation patterns were analyzed by repeated measures ANOVA with post‐hoc comparisons. Motor group recruitment was similar across all pull‐up techniques, with upper limb depression occurring secondary to torso elevation. Stress‐time profiles show significant differences in individual muscle patterns among the three pull‐up variants, with the most marked differences between wide grip and reverse grip. Comparing across techniques, latissimus dorsi was relatively more active in wide pull‐ups (p<0.01); front pull‐ups favored activation of biceps brachii and brachialis (p<0.02); reverse pull‐ups displayed higher proportional rotator cuff activation (p<0.01). Pull‐ups promote stability of the shoulder girdle and activation of scapula stabilizers and performing pull‐ups over their full range of motion is important as different techniques and phases emphasize different muscles. Shoulder rehabilitation and strength & conditioning programs should encourage incorporation of all three pull‐up variants with systematic progression to provide greater global strengthening of the torso and upper limb musculature.
... When performing a DL, these differences may alter both joint angles and moment arms, therefore varying the demands exerted on the forearm musculature when gripping the barbell. Additionally, forearm muscle activation can provide information on training efficiency and strength adaptations (Dickie et al., 2017). Finally, the combined information of muscle activation and exertion levels may potentially help in understanding forearm injuries (O'sullivan and Gallwey, 2002). ...
... For the BS muscle, the electrode site was located approximately three fingers' distance from the lateral epicondyle (Delagi et al., 2011). For the BR, the muscle was palpated in elbow flexion at the cubital fossa, and then traced to the midway point (Dickie et al., 2017). Finally, for the FCU, the muscle was located three fingers distally from the medial epicondyle (Delagi et al., 2011). ...
Muscle activation, peak velocity (PV) and perceived technical difficulty while using three grip variations and three loads during a deadlift exercise (DL) were examined. Twenty-nine resistance-trained athletes (15 males, age: 22.2±2.7 years; 14 females, age: 24.8±7.0 years) performed the DL with 50%, 70% and 90% of their one repetition maximum (1RM) using hook grip (HG), mixed grip (MG) and double overhand (DOH) grip. Surface electromyography (EMG) of the brachialis (BS), brachioradialis (BR) and flexor carpi ulnaris (FCU) was recorded. PV and perceived technical difficulty of each grip were also measured. Regardless of load and grip, females exhibited greater BS activation compared to males (p<0.05; ES=0.69) while males displayed greater BR activation, significant at 90% load (p<0.01; ES=1.01). MG elicited the least BR and FCU activation regardless of load and sex (p<0.01; ES=0.64-0.68) and was consistently ranked as the easiest grip for any load. Males achieved significantly greater PV than females at 50% and 70% (p<0.01; ES=1.72-1.92). Hand orientation did not significantly impact PV. A MG may be beneficial in reducing the overall perceived technical difficulty when performing a maximal DL. Athletes aiming to maximise muscle activation and potentially develop their grip strength should utilise a DOH grip or HG.
... Reported muscular endurance values were computed by multiplying body mass by repetitions completed during two 60s attempts with 60s rest in between. FIS scores were extracted from the International Ski Federation "First Cross-Country List, 2018/2019" (FIS, 2019. Due to sex differences, female scores for each variable were multiplied by the fractional difference between the male and female means, thus normalizing the two populations. ...
... Supporting the importance of muscular endurance indices, 60 second assessments of upper body muscular endurance using a double poling ergometer positively correlates to 10 km classic skiing race speed (Alsobrook & Heil, 2009). Push-ups, pull-ups and sit-ups use similar musculature to those activated during the primary portion of the pole plant phase (Cogley et al., 2005;Dickie et al., 2017;Holmberg et al., 2005;Parfrey et al., 2008). Holmberg and colleagues investigated the DP technique, which is characteristic of greater peak poling forces than the V1 or V2 skates (Millet et al., 1998b). ...
The Internationl Ski Federation (FIS) ranks Nordic skiers internationally based on race performance. This study aimed to determine if a relationship exists between FIS rankings and performance indicators such as maximum oxygen uptake, metabolic economy, and muscular endurance test performance. Muscular endurance (sit-up + pull-up and push-up + pull-up) were the best predictors utilizing stepwise regression resampling cross-validation (66 hold out groups). The sit-up + pull-up regression was a better fit than the push-up + pull-up (R 2 = 0.506 & 0.349, p = 0.053 & 0.203, respectively). Muscular endurance test performance predicts FIS scores better than measures of oxygen consumption measures. Upper-body and core musculature may be an important determinant of performance, as it contributes to generation of propulsive forces in Nordic skiing.
... Franke et al. (2015) examined the activity level of the seated row, incline lat pulldown, and reverse peck deck fly exercises in the shoulder muscles and found that seated row was effective in working the medial part of the shoulder and reverse peck deck fly was effective in working the medial and back parts of the shoulder. Dickie et al. (2017) compared the muscle activity level of different variations in the pull-up exercise and found that the pronation grip variation activates the medial trapezius muscle more than the neutral grip. Also, they did not observe any difference between supination grip and neutral grip. ...
This study aimed to compare the effects of handgrip and range of motion (ROM) variations on muscle activity in different deltoid exercises. 14 resistance-trained men volunteered for 1RM and EMG testing with a load corresponding to 80% of 1RM. The subjects performed three different handgrips during Dumbell Front Raise (DFR), two different ROM variations for Dumbell Lateral Raise (DLR), and two different handgrips during Dumbell Rear Delt Raise (DRDR). Electromyogram (EMG) activity was measured in the anterior, medial, and posterior heads of deltoids. For the DFR exercise, the highest mean EMG activity was greater for the anterior deltoid, and the highest activity was observed in pronate grip (PG) con (51.57%). For the anterior deltoid EMG activity was significantly greater in PG con (51.57%) compared with hammer grip (HG) con (43.36%) (p˂0.05). HG ecc activity (40.36%) was significantly greater than PG ecc (36.4%) in posterior deltoid (p˂0.05). For the DLR exercise, the highest activity was observed in medial deltoid, and for limited ROM (LTR) (20.74%). LTR con activity (19.37%) was significantly greater than full ROM con (FLR) (16.88%) in the anterior head (p˂0.05). For the DRDR exercise, the mean activity was greater in medial deltoid, and HG con showed the highest activity (24.47%). The mean electromyography activity for the posterior deltoid was significantly greater in standard grip (STD) ecc compared with HG ecc (17.3%) (p˂0.05). In conclusion, for the heads of the deltoid muscle, the use of the different handgrip and ROM variations may increase neuromuscular activity.
... Interestingly, the subject inquired about doing pull-ups at a previous visit and was advised against doing so, then came to his following visit with studies showing very high bicep EMG activity during pull-ups. 41,42 These were avoided at this time. The reader is referred to Table 1 for the exercise grip progression used in this case. ...
Background
Rupture of the distal biceps is relatively rare and post-operative protocols are typically vague and are used on many patients, regardless of pre-morbid status. The primary objective is to share the progressive loading strategy used in the rehabilitation of a strongman athlete following a surgical repair of the distal biceps. An additional objective is to highlight the need for individualized protocols and progressions with respect to patient goals and sport demands, as well as the need for shared decision making (SDM) between the medical doctor, patient, and rehabilitation provider.
Case Presentation
The subject is a 39-year-old strong man competitor who suffered a distal biceps rupture while doing a tire flip during training. After having it repaired, the post-operative recovery was unremarkable. The focus of the described intervention was establishing load during rehabilitation exercises that were unique to this individual based on his pre-morbid level of strength and training history as well as the unique demands of his sport.
Outcomes
The patient achieved symmetrical isokinetic strength of the elbow flexors at 60°/second in supine at six months post-operative.
Discussion
The case highlights a successful outcome in a strongman competitor with a distal biceps rupture repair. Typically, protocols are vague and lack specific standards for establishment of load for exercises. Often starting points and progressions are arbitrary and lack rationale tailored to individual needs and/or pre-morbid status. The case offers a framework for establishing and progressing load while also discussing how a shared decision-making model can lead to positive outcomes.
... The pull-up is a form of exercise frequently used in resistance training for various purposes, including building strength and stamina [9] [10]. The biceps brachii muscles are trained and utilized through pull-up training. ...
A pull-up is a type of upper-body exercise that involves the use of both hands. It works by raising the body's head and shoulders and bending the elbows, and extending the shoulders. It can be performed anywhere and is a great way to tone and expand various muscle groups. This study aims to design a device that can count and track the number of pull-up exercises. Pull-Up Counter Device was developed using the Rapid Prototyping model. The product was evaluated by 30 respondents. The result shows that 83.33% of the users strongly agree that the device can display the correct pull-up record on the LCD, and 50% strongly agree that the device can detect pull-up position correctly.
... Different variations of the grip also exist including the two classical hand orientations [24]: the overhand grip (hands in pronation) and the underhand grip (hands in supination). Studies have identified sometimes few [11,28] and sometimes significant differences [30] on muscle activation (i.e. EMG of Biceps Brachii, Pectoralis and Trapezium) depending on the hand orientation used. ...
Pull-ups are usually performed for training in many sports. Different pull-up variations (velocity, hand orientations etc.) can affect the pull-ups performance. While being widely used, athletes can either stop at the bottom of the pull-up (elbow in full extension) or perform non-stop pull-ups. Yet, the physiological and biomechanical impact of such variations are poorly quantified. The objective of this study was to analyze two ways of pull-ups completion: one in which the athletes pause at the bottom of each pull-up (SINGLE) and another in which the athletes perform the pull-ups with no pause between the downward movement and the subsequent upward movement (MULTIPLE). The kinematics and electromyography of the upper limbs and the force generated at the bar were recorded while performing both SINGLE and MULTIPLE pull-ups using two classical hand orientations: the overhand grip and the underhand grip. MULTIPLE pull-ups generated significantly better performance with higher absolute vertical velocities in both the ascent and descent phases (P < 0.05). With MULTIPLE pull-ups, the force applied on the bar was higher at the beginning of the ascent phase and at the end of the descent phase while the force was lower at the top of the pull-ups. These better performances were not accompanied by higher EMG activities during the ascent phase, but a steep increase in muscle activation was observed during the descent phase (P < 0.05). This result showed that, for MULTIPLE pull-ups, muscle and tendon stretch-shortening cycles might be at play in a similar way to that which is observed for the lower limbs during countermovement jumps. Recommendations on pull-ups completion should take into account these new results for better efficiency.
... In future studies, it would be worthwhile to compare the PAPE response in subjects performing one-arm pull-ups in unassisted and assisted forms and also to determine the magnitude of relief more precisely, perhaps based on the velocity of the movement known to be related to RM magnitude (González-Badillo and Sánchez-Medina, 2010;Loturco et al., 2021;Pérez-Castilla and García-Ramos, 2020). The one-arm pull-up is slightly different in movement structure compared to the power slap, and despite the involvement of the same muscle groups, muscle activation patterns may slightly vary (Dickie et al., 2017;Kozin et al., 2020;Leslie and Comfort, 2013). Considering the criterion of biomechanical similarity between complementary exercises (resistance exercise -explosive exercise), weighted pull-ups performed in the traditional two arms manner may be an exercise that fulfils this condition more fully than one-arm pull-ups. ...
This study aimed to compare the acute effects of performing two kinds of pull-ups: traditional, pronated grip pull-ups performed with two arms and additional weight with loading intensity of 5RM and one-arm pull-ups, on specific upper body climbing power. Twenty-four advanced climbers participated in the study. The International Rock Climbing Research Association (IRCRA) Power Slap Test was chosen to assess specific upper body climbing power. All athletes performed the test under three conditions: control (without a conditioning activity) and both kinds of pull-ups as conditioning activities. Results revealed significant improvements in the Power Slap's distance, power, velocity, and force in 5RM weighted pull-ups, but not in one-arm pull-ups. In the latter case, participants reached higher power values after the conditioning stimulus, but the effect size was small. Also, the differences with the remaining variables (power, speed, and force) were non-significant. The results suggest that weighted pull-ups with a 5RM intensity and not one arm pull-ups seem to be an effective PAPE stimulus. Therefore, the former can be used as a conditioning activity before an explosive climbing exercise such as the Power Slap on a campus board.
... There are applications to gait analysis, muscle coordination evaluation, clinical evaluation, and sports performance [4]. Electromyography can provide significant insights into adaptations from exercise programs, and the muscular coordination of specific muscles in strengthening exercises [5][6][7]. However, EMG is not regularly used by exercise professionals when designing programs or interventions for individual athletes and patients. ...
Electromyography (EMG) is a research tool used in gait analysis, muscle coordination evaluation, clinical evaluation and sports techniques. Electromyography can provide an insight into neural adaptations, cross education effects, bilateral contraction deficiencies, and antagonist activity in exercise-related movements. While there are clear benefits to using EMG in exercise-related professions, accessibility, cost, and difficulty interpreting the data limit its use in strength and clinical settings. We propose a practical EMG assessment using the isometric squat to identify compensatory activation patterns and report early observations. Ten healthy participants were recruited. Participants performed a 2-min isometric handgrip protocol and an isometric squat protocol. The isometric handgrip was used to identify the expected EMG amplitude response solely due to fatigue. There was a significant increase in EMG amplitude after 2 min (p < 0.05), with the relative increase of 95% CI (1.4%; 27.4%). This indicates the relative increase in EMG amplitude expected if the only influence was fatigue in the 2-min protocol. In the isometric squat protocol, we identified a number of different muscle activation compensation strategies with relative EMG amplitude increases outside of this bandwidth. One subject demonstrated a quadricep compensation strategy with a 188% increase in activation, while reducing activation in both the hamstrings and lower back by 12%. Exercise professionals can use this information to design exercise programs specifically targeting the unloaded muscles during the isometric squat.
... The biceps brachii (BB) and latissimus dorsi (LD) are the prime movers of the SPU exercise as the glenohumeral joint and elbow joint go through extension and flexion during the concentric phase, respectively, and are considerably more active during the pulling (concentric) and lowering (eccentric) phase of the SPU than other upper body musculature (Dorma, Deakin, & Ness, 2013). Interestingly, Dickie, Faulkner, Barnes and Lark (2017) highlighted that differences in upper body muscle activation are seen when comparing the concentric and eccentric phases of the SPU. Further, changes in approach to performing the SPU exercise has seen changes in muscle activation. ...
The kipping pull-up (KPU) and butterfly pull-up (BPU) are variations of the strict pull-up (SPU) where an athlete uses hollow and arched body positions to gain momentum, before accelerating vertically. Understanding the muscle activity of each of these exercises will help coaches better utilise them within a strength and conditioning programme. The aim of this study was to compare upper and lower body muscle activation between the SPU, KPU and BPU during the concentric and eccentric phases of each exercise. 11 participants had surface electromyography data collected from three upper and three lower body muscles while completing each pull-up variation. Peak EMG data from each phase for each muscle from the SPU were used to normalise peak KPU and BPU EMG data. A repeated measures ANOVA with Bonferroni post hoc testing was used to identify significant differences between each variation. The results show significantly reduced muscle activation in the bicep brachii during the concentric (p < 0.05; d = 1.1) and eccentric (p < 0.05; d = 1.1) phases of the BPU, when compared to the SPU. Activation of the latissimus dorsi was significantly lower during the concentric phase of the KPU (p < 0.02; d = 1.2) and eccentric phase (p < 0.01; d = 1.4) of the BPU in comparison to the SPU. Furthermore, significantly greater muscle activation was shown in the rectus femoris, gluteus maximus and rectus abdominus in both the KPU and BPU, when compared to the SPU. However, results differed within the concentric and eccentric phases. These findings show that both styles of kipping increase lower body muscle activation and decrease upper body activation in comparison to the SPU. Further, due to the different style of kip, the KPU and BPU display different muscle activations during both the concentric and eccentric phases.
... Pull-up 운동과 관련된 선행연구들은 잡는 방법(그립 종류)과 잡는 위치(그립 너비)에 따른 주동근에 미치는 영향에 관한 연구가 대부분 이며[4,11], 그립의 종류에 관한 선행연구의 결과로 Koehler[13]연구에 의하면, 잡는 방법으로 회외(supinated grips)는 상완 이두근과 승모근 의 근활성도가 높게 나타났으며, 회내(pronated grip)와 중립(neutral grips)은 광배근의 근활성도가 높게 나타났다고 보고하였다. 하지만 Kelly & Paul [14]은 pull-up 운동시에 일반적으로 사용하는 회내 그립 (pronated grip)이 광배근 발달에 효과적이라고 생각하지만 이에 대한 근거는 부족하다고 주장하였다. ...
PURPOSE:There are various variables such as exercise posture, exercise intensity, number of repetitions, and rest time of training for muscle strength development, and these variables are intended to stimulate muscle activity. The purpose of this study was to examine the effects of muscle activation according to grip thickness in pull-up exercise.METHODS: Eleven healthy men were randomly crossover design assigned to pull-up exercise (concentric: 1-s, eccentric: 1-s, 2-s/repetition) to failure. Surface electromyography (EMG) was recorded from the forearm flexors/extensors, biceps brachii, trapezius middle/lower and latissimus dorsi for muscle activation. Using the resulting EMG data, which were filtered of electromyogram artifacts, we calculated the root mean squares (RMS).RESULTS: Dependent-sample t-test produced a result, muscle activity in forearm flexors (p<.01), biceps brachii (p<.01), trapezius middle (p<.01), trapezius lower (p<.01) and latissimus dorsi (p<.05) were significantly increased at thick grip compared to normal grip in pull-up exercise.CONCLUSIONS:This study suggested that the thicker the grip, the higher the muscle activation. Using a grip thickness as one of the variables for training programs is considered as a method to stimulate muscle activity.
... No significant associations were found between VO2max and WOD1_Fran, coinciding with the results of Butcher et al. (2015), probably due to the lower number of exercises and thus shorter duration: 90 repetitions in total (45 pull-ups and 45 thrusters). In addition, the pull-up involves low oxygen uptake and is characterized by a pulling movement of the upper limbs with relatively little involvement of the rest of the body (Dickie et al., 2017). ...
CrossFit® is a competitive sport and fitness modality characterized by multiple physical capabilities and multi-joint movements. This study aimed to analyse and classify variables related to CrossFit® competitors' specific performance. Fifteen male CrossFit® competitors were selected (n = 15; 30.57 ± 5.5 years; 1.76 ± 0.06 m; 78.55 ± 9.12 kg). Mean values were obtained for body mass index (25.3 ± 2.14 kg/m 2), 4 skinfolds, 1 repetition maximum in the squat (137.60 ± 19.65 kg) and the bench press (101.67 ± 10.64 kg), maximum pull-ups (18.87 ± 5.05), sit-ups in 60 s (46.60 ± 4.22), peak power in the countermovement jump (3908.04 ± 423.68 W), VO2max with a shuttle run test (47.70 ± 4.79 ml kg-1 ·min-1), and time in the Workout of the Day (WOD) "Fran" (337.13 ± 119.19 s) and "Donkey Kong" (417.47 ± 98.44 s) components. Principal component analysis was conducted to classify variables and to select those most related to each new component ("strength and muscle mass", "adiposity" and "aerobic capacity"). The correlation matrix was analysed, indicating significant correlations between "Donkey Kong" and VO2max (r =-.675; p < .01), suprailiac skinfold (r = .713; p < .01) and sit-ups (r =-.563; p < .05); and between "Fran" and squat (r =-.528; p < .05). Three important components characterizing CrossFit® competitors were identified: "strength and muscle mass", low "adiposity" and "aerobic capacity". Significant relationships between morphofunctional variables and Crossfit® performance were found in Crossfit® competitors.
... The forearm of the human body includes a lot of muscle groups associated with finger movements [27]. For example, extensor indicis muscle, extensor pollicis longus muscle, extensor pollicis brevis muscle, and so on. ...
Soft robot is a new type of flexible robot which can imitate human hand activity. Electromyographic (EMG) signal is an important bioelectrical signal associated with muscle activity. The innovative combination of soft robot and EMG shows great potential. Based on this inspiration, a humanoid soft robotic hand controlled by EMG was proposed. We designed a single finger 3D model for the soft robotic hand and put forward the three-stage cavity structure. The finite element analysis has been performed to obtain the influence of the geometrical parameters including the number of cavities, the shape of the cavity side section, and the pressure in the cavity on the single finger bending performance. The optimal geometrical parameters were obtained. We analyzed the geometrical deformation of the finger simulation model and figured out the relationship between the input pressure of the soft hand and the angle of bending deformation. In addition, we designed and manufactured the soft robotic hand model and its pneumatic system. Twenty-four effective eigenvalues were extracted from the surface EMG signal (sEMG) of the forearm muscle group and ten-kinds-gestures recognizing system was established. Finally, we realized the online sEMG control of the soft robotic hand, so that the soft robotic hand can reproduce the gestures behavior of human. The correct rate of recognition is 96%. Conclusions obtained in this paper provide theoretical support for the development of humanoid soft robotic hand.
... Como técnica, a eletromiografia consiste na aquisição e tratamento do sinal elétrico produzido na musculatura a partir da estimulação de unidades motoras. Estudos recentes têm utilizado a EMG na avaliação da atividade muscular em situações de isquemia induzida [3,4], das regiões submentais [5], de análise biomecânica, onde é feita a análise de quais músculos são ativados em determinado movimento [6], de pacientes pós AVC [7] e de força [8]. ...
The elbow joint plays an essential role in positioning the hand during daily life and self-care activities. This hinge-type joint between the distal humerus and the proximal articular surfaces of the radius and ulna bones acts as a support point for bearing weight and the forearm. The elbow joint has complex biomechanical properties for stability and function. The complexity of the joint, due to the important surrounding ligaments and neurovascular structures, makes surgical interventions very difficult. The elbow is often injured during sports such as shooting, tennis, golf, weightlifting, bowling, and other professional activities requiring frequent joint use. Rehabilitation requires a detailed understanding of elbow joint anatomy and biomechanics. The bone structures that comprise the elbow joint, as well as the joint capsule, ligaments, muscles, biomechanical properties, palpation of the adjacent anatomical structures, and exercises specific to the elbow joint are all defined in this chapter.KeywordsElbow jointAnatomyPalpationBiomechanicsExercise
Background
The three portions of the deltoid muscle (anterior, middle, and posterior) are primary movers of several strengthening exercises and their contribution to different exercises can be measured using surface electromyography.
Purpose
To systematically review studies that evaluated the activation of commonly used exercises and their variations.
Methods
A search was conducted in PubMed (MEDLINE), Web of Science, Scopus and SciELO. Thirty-three studies met the inclusion criteria, evaluating at least one deltoid portion during conventional isotonic exercises (minimum load: 60% of one-repetition maximum or body weight) and reporting normalized values. Similar exercises were grouped, averaged, and ranked according to the resulting activation. Individual exercise variations were also ranked.
Results
For anterior deltoid, horizontal adductions (inclined) and horizontal adductions (horizontal) generated the greatest activation, while the inclined dumbbell fly was the individual exercise with greatest activation; for middle deltoid, abductions and horizontal abductions presented the greatest activation, with lateral raises associated with internal rotation being the exercises producing greatest activation. For posterior deltoid, pull-ups generated greatest activation, with the standard pull-up and the inverted row with a suspension device requiring the greatest individual exercise activation.
Conclusions
These findings can be useful for coaches and practitioners when choosing the most appropriate exercise for strengthening programs.
The brachioradialis muscle (BRD) is one of the main elbow flexors and is often assessed by surface electromyography (sEMG) in physiology, clinical, sports, ergonomics, and bioengineering applications. The reliability of the sEMG measurement strongly relies on the characteristics of the detection system used, because of possible crosstalk from the surrounding forearm muscles. We conducted a scoping review of the main databases to explore available guidelines of electrode placement on BRD and to map the electrode configurations used and authors’ awareness on the issues of crosstalk. One hundred and thirty-four studies were included in the review. The crosstalk was mentioned in 29 studies, although two studies only were specifically designed to assess it. One hundred and six studies (79%) did not even address the issue by generically placing the sensors above BRD, usually choosing large disposable ECG electrodes. The analysis of the literature highlights a general lack of awareness on the issues of crosstalk and the need for adequate training in the sEMG field. Three guidelines were found, whose recommendations have been compared and summarized to promote reliability in further studies. In particular, it is crucial to use miniaturized electrodes placed on a specific area over the muscle, especially when BRD activity is recorded for clinical applications.
Background:
Electromyographic systems are widely used in scientific and clinical practice. The reproducibility and reliability of these measures are crucial when conducting scientific research and collecting experimental data.
Objective:
To test the reliability of surface electromyography signals from both the Flexor Digitorum Superficialis (FDS) and Extensor Carpi Radialis Brevis (ECRB) muscles of both the left and right arms during an individual, static multi-planar maximum voluntary contraction handgrip task using the Myon 320 system (Myon AG, Switzerland).
Methods:
Eight right-handed male participants performed two maximal handgrip tests in five separate wrist positions using both hands. Muscle activity was recorded from both forearms. Reliability was measured using the Standard Error of Measurement (SEM), Coefficient of Variation (CV) and Intra-class correlation coefficients. Wrist joint position correlations within and between the FDS and ECRB muscle activities were also analysed.
Results:
Absolute reliability was shown across all positions for both hands with CV and SEM recorded at below 10%. The output measures indicate that the Myon 320 system (Myon AG, Switzerland) produces good to fair reliability when assessing forearm muscle activity. Correlations in the left FDS muscles were negative. Correlations between the left ECRB and left FDS muscles were variable but positive between the right ECRB and right FDS muscles.
Conclusions:
The data sets retrieved from all participants were reliably evaluated. Wrist position correlations within and between the FDS and ECRB muscles may have been influenced by hand dominance. The findings demonstrate that the methods and systems outlined in this study can be used reliably in future research.
The field of sports engineering is a relatively new discipline of engineering. It connects two very different domains: engineering and sports. Engineers concerned with sports design build customized equipment related to a sportsperson's needs and also measure the sportsperson's performance, the equipment's effectiveness, and analyze how the two interact. Engineering, along with technology today, is playing a key role in not merely enhancing the sportsperson's performance, but in making fitness more safe and attractive. In this study, an exercise regimen is proposed for improving the strength of biceps and triceps of a sportsperson, followed by a proposed structure (equipment) for executing this regimen. The design of this structure is validated using theoretical calculations and simulations on ANSYS software.
Background:
Muscle fatigue seems to be a risk factor in the development of performance-related musculoskeletal disorders (PRMDs) in musicians, but it is unclear how muscle activity characteristics change between musicians with and without PRMDs over a prolonged playing period.
Purpose:
To investigate muscle activity patterns in muscles of the arms, shoulder, and back of high string musicians during prolonged performance.
Methods:
Fifteen professional or university high string musicians were divided into PRMD and non-PRMD groups. All musicians played a chromatic scale, then an individual "heavy" piece for 1 hr, and finally the chromatic scale again. Surface electromyography (sEMG) data were recorded from 16 muscles of the arm, shoulder, and trunk on both sides of the body. Two parameters were analyzed: the percentage load in relation to the respective maximum force during the chromatic scale, and the low-frequency spectrum to determine the fatigue behavior of muscles during the 1-hr play.
Results:
Changes in muscle activation patterns were observed at the beginning and end of the trial duration; however, these varied depending on whether musicians had PRMDs or no PRMDs. In addition, low-frequency spectrum changes were observed after 1 hr of playing in the PRMD musicians, consistent with signs of muscular fatigue.
Conclusion:
Differences in muscle activity appear between high string musicians with and without PRMDs as well as altered frequency spectrum shifts, suggesting possible differential muscle fatigue effects between the groups. The applied sEMG analysis proved a suitable tool for detailed analysis of muscle activation characteristics over prolonged playing periods for musicians with and without PRMDs.
HAND ORIENTATION (SUPINATED, NEUTRAL, PRONATED) AND GRIP WIDTH ARE COMMONLY VARIED DURING PULL-UPS AND LAT PULL-DOWNS IN AN ATTEMPT TO FOCUS THE TRAINING ON SPECIFIC MUSCLE GROUPS OR TO ENSURE THAT THE MOVEMENT IS SPECIFIC TO THE SPORTING ACTION. THE AIM OF THIS ARTICLE WAS TO IDENTIFY IF VARYING GRIP WIDTH AND HAND ORIENTATION EFFECTS MUSCLE ACTIVITY DURING PULL-UPS AND LAT PULL-DOWNS. IT HAS BEEN DEMONSTRATED THAT USING ROTATING HANDLES DURING PULL-UPS OR USING A PRONATED GRIP DURING LAT PULL-DOWNS TENDS TO RESULT IN THE GREATEST ACTIVATION OF THE LATISSIMUS DORSI, WITH NO DIFFERENCE IN LATISSIMUS DORSI ACTIVITY BETWEEN GRIP WIDTHS.
In order to stimulate further adaptation toward a specific training goal(s), progression in the type of resistance training protocol used is necessary. The optimal characteristics of strength-specific programs include the use of both concentric and eccentric muscle actions and the performance of both single- and multiple-joint exercises. It is also recommended that the strength program sequence exercises to optimize the quality of the exercise intensity (large before small muscle group exercises, multiple-joint exercises before single-joint exercises, and higher intensity before lower intensity exercises). For initial resistances, it is recommended that loads corresponding to 8-12 repetition maximum (RM) be used in novice training. For intermediate to advanced training, it is recommended that individuals use a wider loading range, from 1-12 RM in a periodized fashion, with eventual emphasis on heavy loading (1-6 RM) using at least 3-min rest periods between sets performed at a moderate contraction velocity (1-2 s concentric, 1-2 s eccentric). When training at a specific RM load, it is recommended that 2-10% increase in load be applied when the individual can perform the current workload for one to two repetitions over the desired number. The recommendation for training frequency is 2-3 d·wk-1 for novice and intermediate training and 4-5 d·wk-1 for advanced training. Similar program designs are recommended for hypertrophy training with respect to exercise selection and frequency. For loading, it is recommended that loads corresponding to 1-12 RM be used in periodized fashion, with emphasis on the 6-12 RM zone using 1- to 2-min rest periods between sets at a moderate velocity. Higher volume, multiple-set programs are recommended for maximizing hypertrophy. Progression in power training entails two general loading strategies: 1) strength training, and 2) use of light loads (30-60% of 1 RM) performed at a fast contraction velocity with 2-3 min of rest between sets for multiple sets per exercise. It is also recommended that emphasis be placed on multiple-joint exercises, especially those involving the total body. For local muscular endurance training, it is recommended that light to moderate loads (40-60% of 1 RM) be performed for high repetitions (> 15) using short rest periods (< 90 s). In the interpretation of this position stand, as with prior ones, the recommendations should be viewed in context of the individual's target goals, physical capacity, and training status.
Based on electromyographic (EMG) studies, an anterior (in front of the face) wide grip with a pronated forearm has been recommended as the optimal lat pull-down (LPD) variation for strengthening the latissimus dorsi (LD) (Signorile, JF, Zink, A, and Szwed, S. J Strength Cond Res 16: 539-546, 2002; Wills, R, Signorile, J, Perry, A, Tremblay, L, and Kwiatkowski, K. Med Sci Sports Exerc 26: S20, 1994). However, it is not clear whether this finding was because of grip width or forearm orientation. This study aimed to resolve this issue by comparing wide-pronated, wide-supinated, narrow-pronated, and narrow-supinated grips of an anterior LPD. Twelve healthy men performed the 4 grip variations using an experimentally determined load of 70% of 1 repetition maximum. Two trials of 5 repetitions were analyzed for each grip type. Participants maintained a cadence of 2-second concentric and 2-second eccentric phases. The grip widths were normalized for each individual by using a wide grip that corresponded to their carrying width and a narrow grip that matched their biacromial diameter. Surface EMG of the LD, middle trapezius (MT), and biceps brachii (BB) was recorded, and the root mean square of the EMG was normalized, using a maximum isometric voluntary contraction. Repeated-measures analysis of variance for each muscle revealed that a pronated grip elicited greater LD activity than a supinated grip (p < 0.05), but had no influence of grip type on the MT and BB muscles. Based on these findings, an anterior LPD with pronated grip is recommended for maximally activating the LD, irrespective of the grip width (carrying width or biacromial diameter).
To determine the relationships among selected shoulder pulling strength and endurance maneuvers, college men (n = 35) and women (n = 23) were evaluated for 1-repetition maximum (1RM) lat-pull (LPmax), 1RM pull-up (PUmax), lat-pull repetitions-to-fatigue using 80% of 1RM (LPreps), and pull-up repetitions at 80% of 1RM (PUreps). PUmax was determined by adding to or counter-weighting the body mass to achieve one repetition. Men and women performed the 1RM with significantly more weight relative to body mass in the PUmax (1.16 +/- 0.15 and 0.73 +/- 0.09, respectively) than in the LPmax (0.93 +/- 0.17 and 0.55 +/- 0.11, respectively). The correlation between LPmax and PUmax was higher in men (r = 0.78; p < 0.01) than in women (r = 0.44; p > 0.05). Women performed significantly more PUreps (10.5 +/- 2.2) than men (8.1 +/- 1.9) but were equivalent to men in the LPreps (10.0 +/- 2.4 and 9.9 +/- 2.5, respectively). Men performed significantly more LPreps than PUreps, whereas the women were equivalent. Body composition components (lean body mass [LBM] and %fat) affected LPmax and PUmax to a greater degree in men than in women. Maximal strength performance in each lift in each sex could be predicted using the analogous muscular endurance exercise or body composition components.
During the positive work phase of pull-ups, integrated electromyographic signals (EMGs) were obtained from selected muscles of the upper chest, shoulder, upper back, and arm in one male and one female subject of comparable age, height, and body mass. In addition, displacement of body mass as well as acceleration and velocity of body mass were calculated as were force and power. Forward as well as reverse grasps on the horizontal bar were additional variables. Irrespective of bargrasp, the data failed to show sex differences in the electromyographic and biomechanical aspects of pull-up performance, assuming of course applied force and power and therefore number of completions of pull-ups of the free-hanging body were expressed as a function of mass being displaced. Pull-ups research represents a complex and challenging study having many fundamental ramifications, but the methodology we have presented has the integrity and capacity to be utilized in the scrutiny and expansion of pull-ups studies.
No study has yet evaluated the efficacy of British Army basic training in improving material handling performance. Therefore, the purpose of this study was to evaluate the efficacy of the current British Army basic training in improving material handling performance and physical fitness. Forty-seven males (19.4 (3.2) years of age, 1753 (59) mm in height, 71.0 (9.6) kg in weight) and 10 females (21.5 (3.5) years, 1623 (45) mm, 62.5 (5.2) kg) served as subjects. Testing was carried out in the week prior to, and in the final week of, an 11-week basic training course. Maximal box lifts to two different heights, and repetitive lifting and carrying of a 10 kg load did not improve with training. Static (38 cm upright pull) and dynamic (incremental dynamic lift to 145 cm) lifting strength data concurred with the maximal box lift data in that no improvement was observed. Repetitive lifting and carrying of a 22 kg load improved (29.5%, p < 0.001), as did 3.2 km loaded march performance with 25 kg (15.7%, p < 0.001), but march performance with a 15 kg load did not. Predicted VO2max improved from 48.4 to 51.4 ml.kg-1.min-1, a change of 6.1% (p < 0.05). Fat-free mass increased by 0.9 kg (1.5%, p < 0.01), and body fat reduced by 2.7% of body mass (20.1%, p < 0.001), resulting in a loss of 1.2 kg of body mass (1.7%, p < 0.01). It is concluded that basic training in the British Army produces some favourable adaptations in recruits, especially in terms of aerobic fitness. However, the poor development of strength and material handling ability during training fails to improve the ability of soldiers to perform simulated military tasks, and it does little to reduce future injury risk while performing these tasks.
Our purpose in this investigation was to develop and validate a theoretical model for a backpack run test based on how fast one can run 2 miles while wearing a backpack. Using actual unloaded (no backpack) 2-mile-run test data from 59 male service academy cadets, we calculated the average oxygen cost during the run, the equivalent cost if wearing additional weight, and the corresponding estimated run time with the backpack. The correlations between body weight and loaded (backpack weight = 30 kg) run times (r = 0.55 [p < 0.05] and r = 0.12 [p > 0.05], respectively) demonstrate that the bias against heavier runners is eliminated with the backpack run. Given that the backpack run test requires only standard-issue equipment, demonstrates clear occupational and health-related fitness relevance, predicts no apparent body-size bias, and measures work- and health-related components of fitness, we recommend that the military services consider the present data when developing or modifying tests of physical fitness.
In order to stimulate further adaptation toward a specific training goal(s), progression in the type of resistance training protocol used is necessary. The optimal characteristics of strength-specific programs include the use of both concentric and eccentric muscle actions and the performance of both single- and multiple-joint exercises. It is also recommended that the strength program sequence exercises to optimize the quality of the exercise intensity (large before small muscle group exercises, multiple-joint exercises before single-joint exercises, and higher intensity before lower intensity exercises). For initial resistances, it is recommended that loads corresponding to 8-12 repetition maximum (RM) be used in novice training. For intermediate to advanced training, it is recommended that individuals use a wider loading range, from 1-12 RM in a periodized fashion, with eventual emphasis on heavy loading (1-6 RM) using at least 3-min rest periods between sets performed at a moderate contraction velocity (1-2 s concentric, 1-2 s eccentric). When training at a specific RM load, it is recommended that 2-10% increase in load be applied when the individual can perform the current workload for one to two repetitions over the desired number. The recommendation for training frequency is 2-3 d x wk(-1) for novice and intermediate training and 4-5 d x wk(-1) for advanced training. Similar program designs are recommended for hypertrophy training with respect to exercise selection and frequency. For loading, it is recommended that loads corresponding to 1-12 RM be used in periodized fashion, with emphasis on the 6-12 RM zone using 1- to 2-min rest periods between sets at a moderate velocity. Higher volume, multiple-set programs are recommended for maximizing hypertrophy. Progression in power training entails two general loading strategies: 1) strength training, and 2) use of light loads (30-60% of 1 RM) performed at a fast contraction velocity with 2-3 min of rest between sets for multiple sets per exercise. It is also recommended that emphasis be placed on multiple-joint exercises, especially those involving the total body. For local muscular endurance training, it is recommended that light to moderate loads (40-60% of 1 RM) be performed for high repetitions (> 15) using short rest periods (< 90 s). In the interpretation of this position stand, as with prior ones, the recommendations should be viewed in context of the individual's target goals, physical capacity, and training status.
Background
Exercise beliefs abound regarding variations in strength training techniques on muscle activation levels yet little research has validated these ideas. The purpose of the study is to determine muscle activation level, expressed as a percent of a normalization contraction, of the latissimus dorsi, biceps brachii and middle trapezius/rhomboids muscle groups during a series of different exercise tasks.
Methods
The average muscle activity during four tasks; wide grip pulldown, reverse grip pull down [RGP], seated row with retracted scapula, and seated rows with non-retracted scapulae was quantified during two 10 second isometric portions of the four exercises. A repeated measures ANOVA with post-hoc Tukey test was used to determine the influence of exercise type on muscle activity for each muscle.
Results & Discussion
No exercise type influenced biceps brachii activity. The highest latissimus dorsi to biceps ratio of activation occurred during the wide grip pulldown and the seated row. Highest levels of myoelectric activity in the middle trapezius/rhomboid muscle group occurred during the seated row. Actively retracting the scapula did not influence middle trapezius/rhomboid activity.
Conclusion
Variations in latissimus dorsi exercises are capable of producing small changes in the myoelectric activity of the primary movers.
Single-occasion, repeated-measures design.
To determine the magnitude of hip abductor muscle activation during 6 rehabilitation exercises.
Many researchers have reported that hip strengthening, especially of the hip abductors, is an important component of a lower extremity rehabilitation program. Clinicians employ non-weight-bearing and weight-bearing exercise to strengthen the hip musculature; however, researchers have not examined relative differences in muscle activation during commonly used exercises. Information regarding these differences may provide clinicians with a scientific rationale needed for exercise prescription.
Sixteen healthy subjects (mean +/- SD age, 27 +/- 5 years; range, 18-42 years; mean +/- SD height, 1.7 +/- 0.2 m; mean +/- SD body mass, 76 +/- 15 kg) volunteered for this study. Bipolar surface electrodes were applied to the right gluteus medius muscle. We measured muscle activation as subjects performed 3 non-weight-bearing (sidelying right hip abduction and standing right hip abduction with the hip at 0 degrees and 20 degrees of flexion) and 3 weight-bearing (left-sided pelvic drop and weight-bearing left hip abduction with the hips at 0 degrees and 20 degrees of flexion) exercises. Data were expressed as a percent of maximum voluntary isometric contraction of the right gluteus medius. Differences in muscle activation across exercises were determined using a 1-way analysis of variance with repeated measures, followed by a sequentially rejective Bonferroni post hoc analysis to identify differences between exercises.
The weight-bearing exercises demonstrated significantly greater EMG amplitudes (P<.001) than all non-weight-bearing exercises except non-weight-bearing sidelying hip abduction.
The weight-bearing exercises and non-weight-bearing sidelying hip abduction exercise resulted in greater muscle activation because of the greater external torque applied to the hip abductor musculature. Although the non-weight-bearing standing hip abduction exercises required the least activation, they may benefit patients who cannot safely perform the weight-bearing or sidelying hip abduction exercises. Clinicians may use results from this study when designing hip rehabilitation programs.
Cluster randomized trials are increasingly popular. In many of these trials, cluster sizes are unequal. This can affect trial power, but standard sample size formulae for these trials ignore this. Previous studies addressing this issue have mostly focused on continuous outcomes or methods that are sometimes difficult to use in practice.
We show how a simple formula can be used to judge the possible effect of unequal cluster sizes for various types of analyses and both continuous and binary outcomes. We explore the practical estimation of the coefficient of variation of cluster size required in this formula and demonstrate the formula's performance for a hypothetical but typical trial randomizing UK general practices.
The simple formula provides a good estimate of sample size requirements for trials analysed using cluster-level analyses weighting by cluster size and a conservative estimate for other types of analyses. For trials randomizing UK general practices the coefficient of variation of cluster size depends on variation in practice list size, variation in incidence or prevalence of the medical condition under examination, and practice and patient recruitment strategies, and for many trials is expected to be approximately 0.65. Individual-level analyses can be noticeably more efficient than some cluster-level analyses in this context.
When the coefficient of variation is <0.23, the effect of adjustment for variable cluster size on sample size is negligible. Most trials randomizing UK general practices and many other cluster randomized trials should account for variable cluster size in their sample size calculations.
Prospective, single-group, repeated-measures design.
To identify exercises that could be used for strength development and the exercises that would be more appropriate for endurance or stabilization training.
The exercises analyzed are often used in rehabilitation programs for the spine, hip, and knee. They are active exercises using body weight for resistance; thus a clinician is unable to determine the amount of resistance being applied to a muscle group. Electromyographic (EMG) analysis can provide a measure of muscle activation so that the clinician can have a better idea about the effect the exercise may have on the muscle for strength, endurance, or stabilization.
Surface EMG analysis was carried out in 19 males and 11 females while performing the following 9 exercises: active hip abduction, bridge, unilateral-bridge, side-bridge, prone-bridge on the elbows and toes, quadruped arm/lower extremity lift, lateral step-up, standing lunge, and using the Dynamic Edge. The rectus abdominis, external oblique abdominis, longissimus thoracis, lumbar multifidus, gluteus maximus, gluteus medius, vastus medialis obliquus, and hamstring muscles were studied.
In healthy subjects, the lateral step-up and the lunge exercises produced EMG levels greater than 45% maximum voluntary isometric contraction (MVIC) in the vastus medialis obliquus, which suggests that they may be beneficial for strengthening that muscle. The side-bridge exercise could be used for strengthening the gluteus medius and the external oblique abdominis muscles, and the quadruped arm/lower extremity lift exercise may help strengthen the gluteus maximus muscle. All the other exercises produced EMG levels less than 45% MVIC, so they may be more beneficial for training endurance or stabilization in healthy subjects.
Our results suggest these exercises could be used for a core rehabilitation or performance enhancement program. Depending on the individual needs of a patient or athlete, some of the exercises may be more beneficial than others for achieving strength.
This lecture explores the various uses of surface electromyography in the field of biomechanics. Three groups of applications are considered: those involving the activation timing of muscles, the force/EMG signal relationship, and the use of the EMG signal as a fatigue index. Technical considerations for recording the EMG signal with maximal fidelity are reviewed, and a compendium of all known factors that affect the information contained in the EMG signal is presented. Questions are posed to guide the practitioner in the proper use of surface electromyography. Sixteen recommendations are made regarding the proper detection, analysis, and interpretation of the EMG signal and measured force. Sixteen outstanding problems that present the greatest challenges to the advancement of surface electromyography are put forward for consideration. Finally, a plea is made for arriving at an international agreement on procedures commonly used in electromyography and biomechanics.
The deltoid (anterior portion) and pectoralis major (clavicular portion) were evaluated in several execution ways of military press exercises with open and middle grips in order to know their behavior pattern. It was analyzed 24 male volunteers, using a 2-channel TECA TE4 electromyograph and Hewllet Packard surface electrodes. It was observed that the execution variation with open and middle grips does not present any significant difference as for the demanding level neither for the pectoralis major muscle nor the deltoid muscle.
The confusion between the terms open kinetic chain and closed kinetic chain becomes even greater with application to the upper extremity. Upper extremity function is very difficult to define, due to the numerous shoulder positions and the great velocities with which the shoulder can move. Classifying exercises for rehabilitation of the upper extremity is very difficult due to the complexity of the joint. Many definitions and classification systems have been proposed; however, none of these entirely encompass rehabilitation of the upper extremity. Using previous classifications we have developed a Functional Classification System that is designed to serve as a template for upper extremity rehabilitation. This system has been designed to restore functional shoulder stability, which is dependent upon proper scapulothoracic and glenohumeral stability, and humeral control; all of these are in part mediated by neuromuscular mechanisms. The objective of our new Functional Classification System is to restore functional stability of the shoulder by reestablishing neuromuscular control for overhead activities.
THE PULL-UP IS A MULTI-JOINT UPPER-BODY EXERCISE THAT CAN INCREASE SHOULDER GIRDLE STABILITY, UPPER-BODY MUSCULAR PULLING STRENGTH, AND PERFORMANCE OF ACTIVITES REQUIRING HIGH LEVELS OF RELATIVE STRENGTH. THIS EXERCISE AND ITS VARIATIONS CAN BE PROGRESSED, REGRESSED, AND PERFORMED THROUGHOUT A TRAINING YEAR. THIS COLUMN PROVIDES A DETAILED DESCRIPTION AND FIGURES OF THE PROPER EXERCISE TECHNIQUE FOR A PULL-UP.
Abstract This study examined anterior chain whole body linkage exercises, namely the body saw, hanging leg raise and walkout from a push-up. Investigation of these exercises focused on which particular muscles were challenged and the magnitude of the resulting spine load. Fourteen males performed the exercises while muscle activity, external force and 3D body segment motion were recorded. A sophisticated and anatomically detailed 3D model used muscle activity and body segment kinematics to estimate muscle force, and thus sensitivity to each individual's choice of motor control for each task. Gradations of muscle activity and spine load characteristics were observed across tasks. On average, the hanging straight leg raise created approximately 3000 N of spine compression while the body saw created less than 2500 N. The hanging straight leg raise created the highest challenge to the abdominal wall (>130% MVC in rectus abdominis, 88% MVC in external oblique). The body saw resulted in almost 140% MVC activation of the serratus anterior. All other exercises produced substantial abdominal challenge, although the body saw did so in the most spine conserving way. These findings, along with consideration of an individual's injury history, training goals and current fitness level, should assist in exercise choice and programme design.
This study compared a conventional pull-up and chin-up with a rotational exercise using Perfect·Pullup™ twisting handles. Twenty-one men (24.9 ± 2.4 years) and 4 women (23.5 ± 1 years) volunteered to participate. Electromyographic (EMG) signals were collected with DE-3.1 double-differential surface electrodes at a sampling frequency of 1,000 Hz. The EMG signals were normalized to peak activity in the maximum voluntary isometric contraction (MVIC) trial and expressed as a percentage. Motion analysis data of the elbow were obtained using Vicon Nexus software. One-factor repeated measures analysis of variance examined the muscle activation patterns and kinematic differences between the 3 pull-up exercises. Average EMG muscle activation values (%MVIC) were as follows: latissimus dorsi (117-130%), biceps brachii (78-96%), infraspinatus (71-79%), lower trapezius (45-56%), pectoralis major (44-57%), erector spinae (39-41%), and external oblique (31-35%). The pectoralis major and biceps brachii had significantly higher EMG activation during the chin-up than during the pull-up, whereas the lower trapezius was significantly more active during the pull-up. No differences were detected between the Perfect·Pullup™ with twisting handles and the conventional pull-up and chin-up exercises. The mean absolute elbow joint range of motion was 93.4 ± 14.6°, 100.6 ± 14.5°, and 99.8 ± 11.7° for the pull-up, chin-up, and rotational exercise using the Perfect·Pullup™ twisting handles, respectively. For each exercise condition, the timing of peak muscle activation was expressed as a percentage of the complete pull-up cycle. A general pattern of sequential activation occurred suggesting that pull-ups and chin-ups were initiated by the lower trapezius and pectoralis major and completed with biceps brachii and latissimus dorsi recruitment. The Perfect·Pullup™ rotational device does not appear to enhance muscular recruitment when compared to the conventional pull-up or chin-up.
With the objective to know the electromyographic activity normal parameters of the deltoid (anterior portion) and pectoralis major (clavicular portion) muscles in the different modalities of military press exercises with middle grip, we analyzed 24 male volunteers using a two-channel electromyograph TECA TE 4, and Hewllet Packard surface electrodes. It was observed high inactivity levels for PMC in almost all the modalities and the concentration in the active cases, mainly, in the weak potential, while DA presented very high levels of much strong action potentials in all the modalities assessed.
Electromyograms (EMGs) need to be normalized if comparisons are sought between trials when electrodes are reapplied, as well as between different muscles and individuals. The methods used to normalize EMGs recorded from healthy individuals have been appraised for more than a quarter of a century. Eight methods were identified and reviewed based on criteria relating to their ability to facilitate the comparison of EMGs. Such criteria included the magnitude and pattern of the normalized EMG, reliability, and inter-individual variability. If the aim is to reduce inter-individual variability, then the peak or mean EMG from the task under investigation should be used as the normalization reference value. However, the ability of such normalization methods to facilitate comparisons of EMGs is questionable. EMGs from MVCs can be as reliable as those from submaximal contractions, and do not appear to be affected by contraction mode or joint kinematics, particularly for the elbow flexors. Thus, the EMG from an isometric MVC is endorsed as a normalization reference value. Alternatively the EMG from a dynamic MVC can be used, although it is recognized that neither method is guaranteed to be able to reveal how active a muscle is in relation to its maximal activation capacity.
Core strengthening and stability exercises are fundamental for any conditioning training program. Although surface electromyography (sEMG) is used to quantify muscle activity there is a lack of research using this method to investigate the core musculature and core stability. Two types of data reduction are commonly used for sEMG; peak and average rectified EMG methods. Peak EMG has been infrequently reported in the literature with regard to the assessment of core training while even fewer studies have incorporated average rectified EMG data (ARV). The aim of the study was to establish the repeatability of peak and average rectified EMG data during core training exercises and their interrelationship. Ten male highly trained athletes (inter-subject repeatability group; age, 18 ± 1.2 years; height, 176.5 ± 3.2 cm; body mass, 71 ± 4.5 kg) and one female highly trained athlete (intra-subject repeatability group; age; 27 years old; height; 180 cm; weight; 53 kg) performed five maximal voluntary isometric contractions (MVIC) and five core exercises, chosen to represent a range of movement and muscle recruitment patterns. Peak EMG and ARV EMG were calculated for eight core muscles (rectus abdominis, RA; external oblique, EO; internal oblique, IO; multifidis, MF; latissimus dorsi, LD; longissimus, LG; gluteus maximus, GM; rectus femoris, RF) using sEMG. Average coefficient of variation (CV%) for peak EMG across all the exercises and muscles was 45%. This is in comparison to 35% for the ARV method, which was found to be a significant difference (P<0.05), therefore implying that the ARV method is the more reliable measure for these types of exercise. Analysis of the inter-subject and intra-subject CV% values suggest that these exercises and muscles are sufficiently repeatable using sEMG. Five muscles were highly correlated (R>0.70; RA, EO, MF, GM, LG) between peak and ARV EMG suggesting, that for these core muscles, the two methods provide a similar evaluation of muscle activity. However, for other muscles (IO, RF, LD) the relationship was found to range from poor to moderate (R=0.10-0.70). The relationship between peak and ARV EMG was also affected by exercise type. Dynamic low and high-threshold exercises and asymmetrical low-threshold exercises had a moderate correlation between the variables (R=0.74-0.81), while the static exercise showed a poor correlation (R=0.46). It can be concluded that there are similarities between the two EMG variables, however due to the effect of type of exercise and muscle on the EMG data, both methods should be included in any future EMG study on the core musculature and core stability exercises.
Electromyography (EMG) is commonly used to assess muscle activity. Although previous studies have had moderate success in predicting individual intramuscular muscle activity from surface electrodes, extensive data does not exist for the rotator cuff. This study aimed to determine how reliably surface electrodes represent rotator cuff activity during 20 maximal exertions.
Five channels of EMG were recorded on the following rotator cuff muscles: supraspinatus and infraspinatus intramuscular and surface recordings, and teres minor intramuscular recordings. An additional 3 surface electrodes were placed over the upper and middle trapezius and posterior deltoid. Subjects performed ramped maximal voluntary contractions (MVCs) for each muscle, followed by 20 isometric maximal exertions. Linear least squares best fit regressions (unconstrained and constrained with zero-intercept) were used to compare: intramuscular and surface supraspinatus and infraspinatus signals, respectively, and intramuscular teres minor and surface infraspinatus signals.
Relationships existed between wire and surface electrode measurements for all rotator cuff muscles: supraspinatus (r(2)=0.73); teres minor (r(2)=0.61); infraspinatus (r(2)=0.40), however prediction equations indicated large overestimations and offsets.
When appropriate multiplicative coefficients are considered, surface supraspinatus and infraspinatus electrodes may be used to estimate intramuscular supraspinatus and teres minor activations, respectively, in maximal exertions similar to those tested. However, until these relationships are better defined in other postures, intensities and exertion types, the use of surface electrodes to estimate indwelling rotator cuff activity is cautioned against.
Normalization of electromyographic (EMG) amplitudes is necessary in the study of human motion. However, there is a lack of agreement on the most reliable and appropriate normalization method. This study evaluated the reliability of single leg stance (SLS) and maximal voluntary isometric contraction (MVIC) normalization methods and the relationship between these measures for the gluteus maximus (GMax), gluteus medius (GMed), rectus femoris (RF), vastus lateralis (VL), hip adductor group (ADD), and biceps femoris (BF). Surface EMG was recorded in 20 subjects during three 5s trials of SLS and MVIC. SLS and MVIC methods both demonstrated good-to-excellent reliability in all muscles (ICCs>0.80). Intrasubject coefficients of variation were lower for the MVIC method (9-36%) than for the SLS method (20-59%). EMG amplitudes during MVIC and SLS were significantly correlated for all muscles (Pearson r's=0.604-0.905, p<0.005) except GMax (r=0.250, p=0.288). Use of SLS normalization for the RF, VL, and BF is not recommended due to a lack of measurement precision. However, this method is justified in the GMax, GMed, and ADD and may provide a better representation of coordinated muscle function during a functional task.
The purpose of this study was to examine the effectiveness of a commercial abdominal machine (Ab-Slide) and three common abdominal strengthening exercises (abdominal crunch, supine double leg thrust, and side bridge) on activating abdominal and minimizing extraneous (nonabdominal) musculature-namely, the rectus femoris muscle. We recruited 10 males and 12 females whose mean (+/- SD) percent body fat was 10.7 +/- 4 and 20.7% +/- 3.2%, respectively. Electromyographic (EMG) data were recorded using surface electrodes for the rectus abdominis, external oblique, internal oblique, and rectus femoris. We recorded peak EMG activity for each muscle during each of the four exercises and normalized the EMG values by maximum muscle contractions (% MVIC). A two-factor repeated-measures analysis of variance assessed differences in normalized EMG activity among the different exercise variations (p < 0.05). Post hoc analyses were performed using the Bonferroni-adjusted alpha to assess between-exercise pair comparisons (p < 0.002). Gender did not affect performance; hence, data were collapsed across gender. We found a muscle x exercise interaction (F9,189 = 5.2, p < 0.001). Post hoc analyses revealed six pairwise differences. The Ab-Slide elicited the greatest EMG activity for the abdominal muscles and the least for the rectus femoris. The supine double leg thrust could be a problem for patients with low-back pathology due to high rectus femoris muscle activity.
We chose to investigate tibiofemoral joint kinetics (compressive force, anteroposterior shear force, and extension torque) and electromyographic activity of the quadriceps, hamstring, and gastrocnemius muscles during open kinetic chain knee extension and closed kinetic chain leg press and squat. Ten uninjured male subjects performed 4 isotonic repetitions with a 12 repetition maximal weight for each exercise. Tibiofemoral forces were calculated using electromyographic, kinematic, and kinetic data. During the squat, the maximal compressive force was 6139 +/- 1708 N, occurring at 91 degrees of knee flexion; whereas the maximal compressive force for the knee extension exercise was 4598 +/- 2546 N (at 90 degrees knee flexion). During the closed kinetic chain exercises, a posterior shear force (posterior cruciate ligament stress) occurred throughout the range of motion, with the peak occurring from 85 degrees to 105 degrees of knee flexion. An anterior shear force (anterior cruciate ligament stress) was noted during open kinetic chain knee extension from 40 degrees to full extension; a peak force of 248 +/- 259 N was noted at 14 degrees of knee flexion. Electromyographic data indicated greater hamstring and quadriceps muscle co-contraction during the squat compared with the other two exercises. During the leg press, the quadriceps muscle electromyographic activity was approximately 39% to 52% of maximal velocity isometric contraction; whereas hamstring muscle activity was minimal (12% maximal velocity isometric contraction). This study demonstrated significant differences in tibiofemoral forces and muscle activity between the two closed kinetic chain exercises, and between the open and closed kinetic chain exercises.
The purpose of this study was to evaluate and compare four different methods of normalising the amplitude of electromyograms (EMGs), from the biceps brachii. Five males performed isotonic contractions of the elbow flexors with an external force of 50 N, 100 N, 150 N and 200 N. These were followed by a single isometric maximal voluntary contraction (MVC) and ten isokinetic MVCs at 0.35 rad s(-1) intervals between 0.35 rad s(-1) and 3.50 rad s(-1). The processed EMGs recorded from the isotonic contractions were normalised by expressing them as a percentage of: (i) the mean (Dynamic Mean Method) and (ii) the peak EMG from the same contraction (Dynamic Peak Method), (iii) the EMG from the isometric MVC (Isometric MVC Method), and (iv) the EMG from an isokinetic MVC at the same elbow angle and angular velocity (Isokinetic MVC Method). The root mean square difference (RMSD) between the outputs of the Isokinetic MVC and Dynamic Mean methods was significantly greater (P<0.05) than between the Isokinetic MVC method and the Dynamic Peak and the Isometric MVC methods. The small (10%) difference between the Isokinetic MVC and the Isometric MVC Methods was a consequence, firstly, of the lack of difference in EMG recorded from the isometric and isokinetic MVCs and, secondly, the consistency in EMG over the range of motion and at different angular velocities of isokinetic MVC. We conclude that only the Isometric and Isokinetic MVC methods should be used to normalise the amplitude of EMGs from the biceps brachii.
This study aimed at investigating the effects of different hand positions on the electromyographic (EMG) activity of shoulder muscles during the performance of the lat pull-down exercise. Ten healthy men performed 3 repetitions of the lat pull-down exercise using their experimentally determined 10RM (repetition maximum) weight. Four different common variations of the lat pull-down were used: close grip (CG), supinated grip (SG), wide grip anterior (WGA), and wide grip posterior (WGP). Normalized root mean square of the EMG (NrmsEMG) activity for the right posterior deltoid (PD), latissimus dorsi (LD), pectoralis major (PM), teres major (TM), and long head of the triceps (TLH) were recorded using surface electrodes and normalized using maximum voluntary contractions. Repeated measures analysis of variance for each muscle detected statistical differences (p < 0.05) in myoelectric activity among hand positions during both the concentric and eccentric phases of the exercise. During the concentric phase, NrmsEMG results for the LD included WGA > WGP, SG, CG. For the TLH: WGA > WGP, SG, CG and WGP > CG, SG. For the PD: CG, WGA, SG > WGP. For the PM: CG, WGA, SG > WGP. During the eccentric phase, the LD produced the following patterns: WGA > WGP, SG, CG and WGP > CG. The TLH pattern showed WGA > SG and CG. For the PD: CG > WGA, WGP. The results indicate that changes in handgrip position affect the activities of specific muscles during the lat pull-down movement. Also, performance of the lat pull-down exercise using the WGA hand position produces greater muscle activity in the LD than any other hand position during both the concentric or eccentric phases of the movement.
Central activation failure and muscular atrophy are common after knee joint injury. Thus, exercises that aim to stimulate muscular hypertrophy and increase neural drive to the muscle fibers should be used during rehabilitation. This study examined the level of knee joint neuromuscular activation during 4 conventional therapeutic exercises (quadriceps femoris muscle setting, manual lateralization of the patella, rhythmic stabilization, and the pelvic bridging exercise) and 4 heavy resistance exercises (free-weight squat with a barbell, horizontal seated leg press, isolated knee extension with a cam mechanism, and isolated hamstring muscle curl) in young, untrained men who were healthy.
Thirteen male subjects (mean age=25.3 years, SD=3.0) with no previous history of knee injury participated in the study.
Neuromuscular activation during the exercises was defined as the root-mean-square (RMS) electromyographic (EMG) signal normalized to the peak RMS EMG signal of a maximal isometric muscle contraction.
Low levels of neuromuscular activation were found during all conventional exercises (<35%). A limitation may be that only a few of many different conventional exercises were investigated. The highest level of neuromuscular activation (67%-79%) was observed during the open kinetic chain resistance exercises (isolated knee extension and hamstring muscle curl). None of the conventional exercises or heavy resistance exercises were found to preferentially activate the vastus medialis muscle over the vastus lateralis muscle.
The results indicate that heavy resistance exercises should be included in rehabilitation programs to induce sufficient levels of neuromuscular activation to stimulate muscle growth and strength.
The value of electromyography (EMG) is sensitive to many physiological and non-physiological factors. The purpose of the present study was to determine if the torque-velocity test (T-V) can be used to normalize EMG signals into a framework of biological significance. Peak EMG amplitude of gluteus maximus (GMAX), vastus lateralis (VL), rectus femoris (RF), biceps femoris long head (BF), gastrocnemius medialis (GAS) and soleus (SOL) was calculated for nine subjects during isometric maximal voluntary contractions (IMVC) and torque-velocity bicycling tests (T-V). Then, the reference EMG signals obtained from IMVC and T-V bicycling tests were used to normalize the amplitude of the EMG signals collected for 15 different submaximal pedaling conditions. The results of this study showed that the repeatability of the measurements between IMVC (from 10% to 23%) and T-V (from 8% to 20%) was comparable. The amplitude of the peak EMG of VL was 99+/-43% higher (p<0.001) when measured during T-V. Moreover, the inter-individual variability of the EMG patterns calculated for submaximal cycling exercises differed significantly when using T-V bicycling normalization method (GMAX: 0.33+/-0.16 vs. 1.09+/-0.04, VL: 0.07+/-0.02 vs. 0.64+/-0.14, SOL: 0.07+/-0.03 vs. 1.00+/-0.07, RF: 1.21+/-0.20 vs. 0.92+/-0.13, BF: 1.47+/-0.47 vs. 0.84+/-0.11). It was concluded that T-V bicycling test offers the advantage to be less time and energy-consuming and to be as repeatable as IMVC tests to measure peak EMG amplitude. Furthermore, this normalization method avoids the impact of non-physiological factors on the amplitude of the EMG signals so that it allows quantifying better the activation level of lower limb muscles and the variability of the EMG patterns during submaximal bicycling exercises.
The ABC of EMG: A Practical Introduction to Kinesiological Electromyography
- P Konrad
Konrad, P., 2006. The ABC of EMG: A Practical Introduction to Kinesiological
Electromyography. Noraxon, USA.