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Abstract

The purpose of this experiment was to determine whether free weight or Smith machine squats were optimal for activating the prime movers of the legs and the stabilizers of the legs and the trunk. Six healthy participants performed 1 set of 8 repetitions (using a weight they could lift 8 times, i.e., 8RM, or 8 repetition maximum) for each of the free weight squat and Smith machine squat in a randomized order with a minimum of 3 days between sessions, while electromyographic (EMG) activity of the tibialis anterior, gastrocnemius, vastus medialis, vastus lateralis, biceps femoris, lumbar erector spinae, and rectus abdominus were simultaneously measured. Electromyographic activity was significantly higher by 34, 26, and 49 in the gastrocnemius, biceps femoris, and vastus medialis, respectively, during the free weight squat compared to the Smith machine squat (p < 0.05). There were no significant differences between free weight and Smith machine squat for any of the other muscles; however, the EMG averaged over all muscles during the free weight squat was 43% higher when compared to the Smith machine squat (p < 0.05). The free weight squat may be more beneficial than the Smith machine squat for individuals who are looking to strengthen plantar flexors, knee flexors, and knee extensors.

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... The loaded barbell squat is a multi-joint exercise for which the prime movers are the quadriceps, hamstrings and gluteals. The squat has neuromuscular as well as biomechanical similarities to jumping and running and is therefore a commonly used exercise to increase muscle strength among athletes across a range of sports (1). Depending on the athletes' goals, the squat can be performed using several alternative techniques, e.g., squatting with the barbell lower down on the back increases hip flexion and reduces knee flexion (2), whereas gluteus maximus activation has been shown to increase when using a wider foot placement (3) and when squatting deeper (>90 • knee flexion) (4). ...
... It is often debated whether performing squats with the barbell resting freely on the shoulders or using a Smith machine is preferable for leg muscle strength training. Current evidence indicates that when the squat is performed in a fixed vertical movement path, greater absolute loads can be lifted (1,8). Schwanbeck et al. observed less gastrocnemius, biceps femoris and vastus medialis activation for Smith machine squats compared with a free movement path among six healthy individuals with strength training experience when using a load equivalent to their eight-repetition maximum (1). ...
... Current evidence indicates that when the squat is performed in a fixed vertical movement path, greater absolute loads can be lifted (1,8). Schwanbeck et al. observed less gastrocnemius, biceps femoris and vastus medialis activation for Smith machine squats compared with a free movement path among six healthy individuals with strength training experience when using a load equivalent to their eight-repetition maximum (1). When squatting with a lower load (29.5 kg and 60% of body weight), Andersson et al. reported less activation of the soleus muscle, but greater activation of the vastus lateralis and no difference in biceps femoris activation in 14 competitive male athletes when squatting in the Smith machine compared with free weight squats (6). ...
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Introduction Traditional recordings of muscle activation often involve time-consuming application of surface electrodes affixed to the skin in laboratory environments. The development of textile electromyography (EMG) electrodes now allows fast and unobtrusive assessment of muscle activation in ecologically valid environments. In this study, textile EMG shorts were used to assess whether performing squats with the barbell resting freely on the shoulders or using a Smith machine for a fixed barbell movement path is preferable for maximizing lower limb muscle activation. Methods Sixteen athletes performed free and fixed barbell squats in a gym with external loads equivalent to their body mass. Quadriceps, hamstrings and gluteus maximus activation was measured bilaterally with textile EMG electrodes embedded in shorts. Results Mean quadriceps activation was greater for the free compared with the fixed movement path for the right (mean difference [MD] 14μV, p = 0.04, η p ² = 0.28) and left leg (MD 15μV, p = 0.01, η p ² = 0.39) over the entire squat and specifically during the first half of the eccentric phase for the left leg (MD 7μV, p = 0.04, d = 0.56), second half of the eccentric phase for both legs (right leg MD 21μV, p = 0.05, d = 0.54; left leg MD 23μV, p = 0.04, d = 0.52) and the first half of the concentric phase for both legs (right leg MD 24μV, p = 0.04, d = 0.56; left leg MD 15μV, p = 0.01, d = 0.72). Greater hamstrings activation for the free path was seen for the second half of the eccentric phase (left leg MD 4μV, p = 0.03, d = 0.58) and first half of the concentric phase (right leg MD 5μV, p = 0.02, d = 0.72). No significant differences were found for gluteus maximus. Discussion Textile EMG electrodes embedded in shorts revealed that to maximize thigh muscle activity during loaded squats, a free barbell movement path is preferable to a fixed barbell movement path.
... A major part of the studies found the main activity on the vastus lateralis, vastus medialis, and rectus femoris, in this order (Aspe & Swinton, 2014;Contreras et al., 2015Contreras et al., , 2016da Silva et al., 2017;Delgado et al., 2019;Ebben et al., 2009;Eliassen et al., 2018;Gorsuch et al., 2013;Hammond et al., 2016;Iversen et al., 2017;Korak et al., 2018;Robbins, 2011;Schwanbeck et al., 2009;Wu et al., 2019;Yavuz et al., 2015). Only one study found major activation on the biceps femoris than on each of these three aforementioned muscles . ...
... Regarding the activation on the gluteus and hamstrings, while some authors observed a greater activation on the gluteus maximus (Caterisano et al., 2002;Fauth et al., 2010;McCurdy et al., 2018), others reported a higher activity on the hamstrings Delgado et al., 2019;Gullett et al., 2009). Only three authors reported activation levels on the muscles of the calves when performing a high-bar squat (Aspe & Swinton, 2014;da Silva et al., 2017;Schwanbeck et al., 2009). ...
... In one study, activation patterns were the same as those reported in the high-bar squat (Schwanbeck et al., 2009). In the study of Blanpied et al. (1999) major activation levels were observed on the gluteus maximus than on the quadriceps or the hamstring. ...
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The squat is one of the most commonly used resistance exercises for performance and health due to its biomechanical and neuromuscular similarities to a wide range of athletic and everyday activities. There is a large number of squat variations (based on the descent depth, width of the stance, bar placement) with significant biomechanical and neuromuscular differences between them. The aim of this study was to systematically review the scientific literature to gather data on the muscular activation of the lower limb during different variants of the squat exercise. High-bar squat (full range of motion, to parallel and partial range of motion), low-bar squat, front squat, overhead squat and guided squat on Smith machine were included in the analysis. 30 articles met the inclusion criteria and were reviewed. Quality of the included studies was analysed with the PEDro scale. Main findings were that in the squat exercise activation of the knee-extensors is predominant. However, different activation patterns were observed with different distances between the feet, different depths, hips rotation or flexion, intensities. For instance, low-bar squat involves a greater hip hinge and thus, provokes major activation on the hip-extensors than other squat variations. It is worth highlighting that similar activation patterns were observed between the front squat and the high-bar squat. The variation with least activation was the guided squat. The evidence presented in this study may help the strength and conditioning professionals and practitioners with the exercise selection depending on the muscular targets and the individual characteristics of the athlete. Keywords: Electromyographic activity; Resistance exercise; Quadriceps; Gluteus; Hamstrings; Calves.
... However, the present study showed a significant difference between the SP and BP, and between the SP and DF (Figure 1), which might be partially explained by the use of free weights instead of a machine. Similarly, sEMG-based studies have shown greater muscle activation in free weight exercises when compared to machines in the AD muscle (McCaw and Friday, 1994;Schick et al., 2010;Schwanbeck et al., 2009). Thus, the SP can also be an effective exercise for the activation of the AD based on the movement of the shoulder (abduction associated with external rotation of the glenohumeral joint) (Liu et al., 1997), favoring the AD and MD activation, as shown in Figures 1 and 3. ...
... Contrary to the results of the present study, Botton et al. (2013) reported higher MD muscle activity during cable/free weight LR compared to SP executed on a Smith machine. This difference may be related to the type of equipment used (free weight vs. machine) where greater activation is observed in primary motor and stabilizer muscles (McCaw and Friday, 1994;Schwanbeck et al., 2009). Thus, the use of the Smith machine in the SP (Botton et al., 2013) may have affected muscle activation by promoting greater stability during exercise execution. ...
... A limitation of the study is the difficulty in comparing the workload (60% 1RM) used in the present investigation to collect the sEMG signal with workloads used in other studies (Botton et al., 2013;Franke et al., 2015;McCaw and Friday, 1994;Schick et al., 2010;Schwanbeck et al., 2009). Although classic (McCaw and Friday, 1994) and current (Muyor et al., 2019) studies have used 60% 1RM workloads for sEMG signal collection, these results should be interpreted with caution as exercise intensity may modify the Journal of Human Kinetics -volume 75/2020 http://www.johk.pl ...
Article
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The aims of this study were to compare muscle activity of the anterior deltoid, medial deltoid, and posterior deltoid in the bench press, dumbbell fly, shoulder press, and lateral raise exercises. Thirteen men experienced in strength training volunteered for the study. Muscle activation was recorded during maximum isometric voluntary contraction (MVIC) for data normalization, and during one set of 12 repetitions with the load of 60% 1RM in all exercises proposed. One-way repeated-measures ANOVA with Bonferroni's posthoc was applied using a 5% significance level. For anterior deltoid, the shoulder press (33.3% MVIC) presented a significantly higher level of activation when compared to other exercises. Also, no significant difference was found between the bench press (21.4% MVIC), lateral raise (21.2% MVIC), and dumbbell fly (18.8% MVIC). For the medial deltoid, the lateral raise (30.3% MVIC) and shoulder press (27.9% MVIC) presented a significantly higher level of activity than the bench press (5% MVIC) and dumbbell fly (3.4% MVIC). Besides, no significant difference was found between the bench press and the dumbbell fly. For the posterior deltoid, the lateral raise (24% MVIC) presented a significantly higher level of activation when compared to other exercises. For the posterior deltoid portion, the shoulder press (11.4% MVIC) was significantly more active than the bench press (3.5% MVIC) and dumbbell fly (2.5% MVIC). Moreover, no significant difference was found between the bench press and the dumbbell fly. In conclusion, the shoulder press and lateral raise exercises showed a higher level of muscle activation in the anterior deltoid and medial deltoid when compared to the bench press and dumbbell fly exercises.
... However, the present study showed a significant difference between the SP and BP, and between the SP and DF (Figure 1), which might be partially explained by the use of free weights instead of a machine. Similarly, sEMG-based studies have shown greater muscle activation in free weight exercises when compared to machines in the AD muscle (McCaw and Friday, 1994;Schick et al., 2010;Schwanbeck et al., 2009). Thus, the SP can also be an effective exercise for the activation of the AD based on the movement of the shoulder (abduction associated with external rotation of the glenohumeral joint) (Liu et al., 1997), favoring the AD and MD activation, as shown in Figures 1 and 3. ...
... Contrary to the results of the present study, Botton et al. (2013) reported higher MD muscle activity during cable/free weight LR compared to SP executed on a Smith machine. This difference may be related to the type of equipment used (free weight vs. machine) where greater activation is observed in primary motor and stabilizer muscles (McCaw and Friday, 1994;Schwanbeck et al., 2009). Thus, the use of the Smith machine in the SP (Botton et al., 2013) may have affected muscle activation by promoting greater stability during exercise execution. ...
... A limitation of the study is the difficulty in comparing the workload (60% 1RM) used in the present investigation to collect the sEMG signal with workloads used in other studies (Botton et al., 2013;Franke et al., 2015;McCaw and Friday, 1994;Schick et al., 2010;Schwanbeck et al., 2009). Although classic (McCaw and Friday, 1994) and current (Muyor et al., 2019) studies have used 60% 1RM workloads for sEMG signal collection, these results should be interpreted with caution as exercise intensity may modify the Journal of Human Kinetics -volume 75/2020 http://www.johk.pl ...
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Full-text available
The aims of this study were to compare muscle activity of the anterior deltoid, medial deltoid, and posterior deltoid in the bench press, dumbbell fly, shoulder press, and lateral raise exercises. Thirteen men experienced in strength training volunteered for the study. Muscle activation was recorded during maximum isometric voluntary contraction (MVIC) for data normalization, and during one set of 12 repetitions with the load of 60% 1RM in all exercises proposed. One-way repeated-measures ANOVA with Bonferroni's posthoc was applied using a 5% significance level. For anterior deltoid, the shoulder press (33.3% MVIC) presented a significantly higher level of activation when compared to other exercises. Also, no significant difference was found between the bench press (21.4% MVIC), lateral raise (21.2% MVIC), and dumbbell fly (18.8% MVIC). For the medial deltoid, the lateral raise (30.3% MVIC) and shoulder press (27.9% MVIC) presented a significantly higher level of activity than the bench press (5% MVIC) and dumbbell fly (3.4% MVIC). Besides, no significant difference was found between the bench press and the dumbbell fly. For the posterior deltoid, the lateral raise (24% MVIC) presented a significantly higher level of activation when compared to other exercises. For the posterior deltoid portion, the shoulder press (11.4% MVIC) was significantly more active than the bench press (3.5% MVIC) and dumbbell fly (2.5% MVIC). Moreover, no significant difference was found between the bench press and the dumbbell fly. In conclusion, the shoulder press and lateral raise exercises showed a higher level of muscle activation in the anterior deltoid and medial deltoid when compared to the bench press and dumbbell fly exercises.
... Studies comparing muscle strength using the free weight squat and Smith machine squat methods demonstrated that free weight squat presents better strength gain in the thigh muscles [52]. However, increased musculature increases PFJF overload [25] due to instability during movement [52]. ...
... Studies comparing muscle strength using the free weight squat and Smith machine squat methods demonstrated that free weight squat presents better strength gain in the thigh muscles [52]. However, increased musculature increases PFJF overload [25] due to instability during movement [52]. ...
Article
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Patellofemoral pain syndrome (PFPS) is highly prevalent; it can cause severe pain and evolve into progressive functional loss, leading to difficulties performing daily tasks such as climbing and descending stairs and squatting. This systematic review aimed to find evidence, in the literature, of squat movements that can cause or worsen PFPS. This work was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement, and its protocol was registered in PROSPERO (CRD42019128711). From the 6570 collected records, 37 were included. From these 37 articles, 27 present a causal relationship between knee flexion and PFPS, 8 describe a relationship, considering the greater existence of muscle contractions, and one article did not describe this relationship in its results. The main limitations stem from the fact that different studies used different evaluation parameters to compare the force exerted on the patellofemoral joint. Furthermore, most studies are focused on sports populations. After analysing the included works, it was concluded that all squat exercises can cause tension overload in the knee, especially with a knee flexion between 60° and 90° degrees. The main causal/worsening factors of PFPS symptoms are the knee translocation forward the toes (on the same body side) when flexing the knee, and the muscle imbalance between the thigh muscles.
... Free-weight training presents advantages such as being less expensive, more versatile, better simulating the movements demanded by sports activity, and developing greater power. In addition, free-weight training may allow greater recruitment of muscle mass, since the machines provide a stable environment and free-weights require more stabilization and balance with greater activation in bench press (Schick et al. 2010) and squat exercises (Schwanbeck et al. 2009), although this aspect may be determined by the intensity of the load (McCaw and Friday 1994). This greater activation occurs in the muscles implicated in the stabilization of the movement, since activation of the trunk has been shown to be similar when performing a squat both in the smith machine and in free-weights (Schwanbeck et al. 2009). ...
... In addition, free-weight training may allow greater recruitment of muscle mass, since the machines provide a stable environment and free-weights require more stabilization and balance with greater activation in bench press (Schick et al. 2010) and squat exercises (Schwanbeck et al. 2009), although this aspect may be determined by the intensity of the load (McCaw and Friday 1994). This greater activation occurs in the muscles implicated in the stabilization of the movement, since activation of the trunk has been shown to be similar when performing a squat both in the smith machine and in free-weights (Schwanbeck et al. 2009). This greater activation in free-weight training causes an increase in anabolic response to training in men but not in women (Mitchell et al. 2013). ...
Chapter
Recent classifications of resistance training methods classify them in gravitational, to move the resistance we will have to apply an acceleration greater than the force of the gravity (9.81 m·s⁻¹), and non-gravitational methods that allow us to work in multiple directions, not being exclusively conditioned by gravity. Bodyweights training, also known as calisthenic exercise; Free-weights training, weight lifting through barbells, dumbbells, and kettlebells; inertial devices, how flywheel devices that an active stretch, while trying to brake an external resistance that exceeds the capacity of the muscle; and external resistance variable resistance, where resistance varies throughout range of motion are, among others, the main methods of resistance training currently. In this chapter, a contextualization of them will be carried out, exposing those essential aspects that it is necessary to know from a practical application and allowing the reader to understand the following chapters where each of them will be addressed in depth.
... Optimal athletic performance greatly depends on the ability to produce, transfer, and control force and motion from one bodily segment to the next as well as to attenuate perturbations and maintain an upright trunk posture (Kibler, IJKSS 8(4):51-58 2007;Yaggie & Campbell, 2006). Studies have demonstrated that core skeletal muscle is activated to a greater degree during IRT when standing, sitting, or laying down on unstable surfaces compared to stable surfaces when the load or intensity is matched (Campbell, Kutz, Morgan, Fullenkamp, & Ballenger, 2014;Schwanbeck, Chilibeck, & Binsted, 2009). Although, IRT on unstable surfaces typically requires a substantially lower load for the safe completion of the exercise leading to reduced force generation and activation of phasic skeletal muscles. ...
... Investigations have demonstrated that squats performed with a barbell elicit greater phasic and core skeletal muscle activation compared to squats performed with the barbell allowed to move in only a single fixed plane (e.g. Smith machine) (Anderson & Behm, 2005;Fletcher & Bagley, 2014;Schwanbeck et al., 2009). Some strength and conditioning professionals have taken the unstable load a step forward by allowing the lifted object's mass to accelerate randomly during a squat (Cullen-Carroll, Larson, & Campbell, 2017;Fletcher & Bagley, 2014;Lawrence & Carlson, 2015). ...
Article
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Background: Acute studies suggest that resistance training with an unstable load suspended from the barbell increases core muscle activation with negligible detrimental effects on phasic muscle activation and force production compared to traditional barbell loading, but the effect of a suspended load program on athletic performance is unclear. Objective: The purpose of this study was to assess the effect of a six-week program where the back-squat was performed with a suspended load (SL) on vertical jump (VJ), change of direction ability (COD), single-leg balance, and one repetition maximum squat load (1RM). Methods: Thirty-two collegiate baseball players (20.4 ± 1.4 y, 86.0 ± 11.0 kg, 1.82 ± .065 m) were assigned to perform the back-squat with SL or traditional loading (CON). Additional exercises were done with traditional loading. Athletes completed VJ, T-tests to measure COD, star excursion balance test (SEBT) to measure single-leg balance, and 1RM PRE and POST program. A MANOVA was used to assess the dependent variables. Significance was set to p < .05. Results: Effect of group × time (p = .152) and group (p = .095) were not significant, indicating CON and SL had similar performance. Effect of time (p < .0001) was significant, suggesting POST performance improved relative to PRE. When groups were pooled, 1RM (p < .0001) and T-test (p = .038) improved, but VJ (p = .255) and SEBT (p = .167) did not improve. Conclusion: Performing squats with SL does not appear to be detrimental to development during a six-week program.
... These systems are incorporated into compression athletic shorts, predominantly analyzing lower extremity thigh muscles (Finni et al., 2007;Lynn et al., 2018;Smith, 2019). sEMG measurements collected from the quadriceps individually from the three vastii muscles and from the rectus femoris are commonly used to quantify performance in voluntary isometric contractions (Caterisano et al., 2002;Clarys & Cabri, 1993;Jang et al., 2018;Schwanbeck et al., 2009). Moreover, different types of squats such as the back squat, free weight squat, Smith machine squat, and wall sit squat have also been analyzed using sEMG recordings from the quadriceps group of muscles (Ebben & Jensen, 2002;Nishiwaki et al., 2006;Schwanbeck et al., 2009;Slater & Hart, 2017;Yuen et al., 2019). ...
... sEMG measurements collected from the quadriceps individually from the three vastii muscles and from the rectus femoris are commonly used to quantify performance in voluntary isometric contractions (Caterisano et al., 2002;Clarys & Cabri, 1993;Jang et al., 2018;Schwanbeck et al., 2009). Moreover, different types of squats such as the back squat, free weight squat, Smith machine squat, and wall sit squat have also been analyzed using sEMG recordings from the quadriceps group of muscles (Ebben & Jensen, 2002;Nishiwaki et al., 2006;Schwanbeck et al., 2009;Slater & Hart, 2017;Yuen et al., 2019). Additionally, sEMG was reported to be a reliable method for assessing reproducibility of muscle activation during controlled dynamic ballistic movements including jump landings and cutting (Fauth et al., 2010). ...
Article
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Background: Recent innovations in surface electromyographic (sEMG) technology have enabled the measurement of muscle activity using smart textiles. Objective: In this study, the StriveTM Sense3 performance monitoring system is evaluated against a research-grade system, NoraxonTM, in measuring activity during the back squat exercise. Method: Seventeen participants performed three total trials of the squat exercise with a progressive load for individual trials equal to 30%, 60%, and 80% of their estimated maximum 1RM (one-repetition maximum). sEMG measurements from the rectus femoris were captured for the left and right leg by both systems. Pearson product-moment correlation coefficient (r) and intraclass correlation coefficient (ICC) values were computed for each trial to assess concurrent validity and interrater reliability of the StriveTM Sense3 device. Additionally, five coaches at the collegiate- and professional-level of Men’s Basketball speak from an autoethnographic frame to the findings from this study. Results: Results ranged from “Poor” to “Excellent” validity and “Poor to Moderate” to “Excellent” reliability, with a majority of trials achieving “Good” or better results across all loads [93% trials: r >= 0.7; 87% trials: lower ICC 95% CI bound >= 0.75 (absolute sEMG); 98% trials: lower ICC 95% CI bound >= 0.75 (normalized sEMG)]. Higher validity and reliability for medium and heavy loads were observed in comparison to the light load, and several outliers indicate the need for coaches to lubricate sensors and ensure proper fit to collect accurate data. Conclusion: Examining results alongside practitioner feedback indicate the StriveTM Sense3 system is capable of tracking sEMG activity in comparison to a research-grade system.
... A possible explanation for the results observed in the present study may be related to the muscular stretching of the biceps brachii in the bench press exercise and the gastrocnemius in the back squat exercise (Bryanton et al., 2012;Lehman, 2005;Schwanbeck et al., 2009). Analyzing these exercises individually, it can be observed that, in the eccentric phase of bench press exercise, there is a stretching of the long and short heads of the biceps brachii as the bar approaches the chest. ...
... Analyzing these exercises individually, it can be observed that, in the eccentric phase of bench press exercise, there is a stretching of the long and short heads of the biceps brachii as the bar approaches the chest. The same may have occurred with the gastrocnemius muscle: the stretching occurred in the eccentric phase of the back squat exercise due to ankle dorsiflexion (Bryanton et al., 2012;Schwanbeck et al., 2009). Thus, it is possible to speculate that such a procedure may have prefatigued the gastrocnemius and biceps brachii and negatively influenced total work volume in the plantar flexion and biceps curl when the multi-joint exercises (i.e. ...
Article
Objective The purpose of this study was to verify the acute effects of different exercise orders and rest intervals between sets on young athletes performance. Method Sixteen young male football players (73.2 ± 4.8 kg, 177.5± 5.1 cm, BMI 23.2 ±1.1, 19.8 ± 0.9 years) completed six experimental strength training (ST) sessions with different exercise order sequences(A and B) and rest interval lengths (one minute, three minutes, and self-selected).In Sequence A the exercises were: bench press (BP), back squat (BS), biceps curl (BC) and plantar flexion (PF); while Sequence B was performed in the opposite order (i.e. PF, BC, BS and BP).The total work volume (TWV) per exercise (sets x repetitions x load) and per training session (sum of the TWV of all exercises) were evaluated for all ST sessions. Results BC and PF exercises presented higher TWV in sequence B (p≤0.05). Already, the exercises BP, BS and PF presented higher TWV with three minutes and self-selected rest intervals (p≤0.05). The three-minute and self-selected rest intervals presented higher values of TWV per training session compared to the one-minute rest interval (p≤0.05). Conclusion The exercise order influenced certain exercises (BC and PF), which presented higher TWV when positioned at the beginning of a sequence. While the longer rest intervals (three minutes and self-selected) resulted in higher TWV per exercise (BP, BS and PF) and per training session. These results suggest that self-selected rest interval can be implemented to increase training efficiency in young athletes.
... One possible reason for this uniformly higher muscle activation may be due to differences in belt squat designs. Previous studies have shown that exercises in which the weight moves along a ixed track have signi icantly less muscle activation than free weight exercises [11][12][13]. Schwanbeck, et al. [12] investigated the EMG activity of a free weight squat as compared to a Smith machine and found 43% higher muscle activation when using the free weight squat. It was surmised that the closed chain task increases knee compressive forces and stimulated a joint co-contraction. ...
... Previous studies have shown that exercises in which the weight moves along a ixed track have signi icantly less muscle activation than free weight exercises [11][12][13]. Schwanbeck, et al. [12] investigated the EMG activity of a free weight squat as compared to a Smith machine and found 43% higher muscle activation when using the free weight squat. It was surmised that the closed chain task increases knee compressive forces and stimulated a joint co-contraction. ...
... Hem fiziksel aktivite olarak yapılan egzersizlerde hem de farklı spor branşları için kuvvet, önemli bir performans göstergesidir. 1 Kuvvet antrenmanı planlamadan önce bireylerin, mevcut performansının belirlenmesi ve bu performansa göre egzersiz yüklerin oluşturulması gerekir, bir tekrar maksimum (1-TM) kuvvet testi, kas kuvvetinin güvenilir bir göstergesidir. 2 Kullanılan program türü ve kas aktivitelerin ölçülü reçetesi, yoğunluğu, volümü, egzersiz seçimi ve uygulaması, setler arası dinlenme süreleri ve egzersiz sıklığı gibi unsurlar kuvvet artışının büyüklüğünü etkileyebilir. [3][4][5] Kondisyon makinesinde yapılan egzersizler, tek eklemde ya da büyük kas gruplarında etkili olurken, serbest ağırlıklarla yapılan çok eklemli egzersizler ise tek eklemli ya da büyük kas gruplarının yanı sıra bir kas üzerinde daha baskındır. 6 Tek eklemli egzersizler hedef alındığında, özel bir kas grubu için kullanılır ve uygulanan teknik ve beceriyi azaltmasından dolayı daha az sakatlık riski oluşturacağına inanılmaktadır. ...
... Buna karşın SA ve M uygulamaları karşılaştırıldığında, M'de sınırlı vücut hareketi ve sabit eklem hareketleri nedeniyle SA'ya göre daha az sinir aktivasyonu görülmektedir. 4 Schwanbeck ve ark.nın araştırmalarında SA ile yapılan squat hareketinde M'ye göre %43 daha fazla elektromiyografik aktivite olduğunu vurgulayarak, SA çalışmalarının daha etkili olabileceğini rapor etmişlerdir. 5 Çalışmamızda ise her 2 grubun 1-TM kuvvet performanslarının, squat ve bench press hareketlerinde M performansının, SA'dan daha yüksek olduğu tespit edilmiştir. Kuvvet egzersizlerinde SA ve M uygulamalarında oluşan maksimal kuvvet performans farkının, M'ye göre SA ile hareket esnasında ağırlığı kontrol edebilmek için daha fazla çaba harcanmasından kaynaklandığı düşünülmektedir. ...
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Smith Ağırlık Makinesi ve Serbest Ağırlık Karşılaştırması: Farklı Yüklerin ve Antrenman Tecrübesinin Set Tekrarları Üzerine Etkisi https://www.turkiyeklinikleri.com/article/en-smith-agirlik-makinesi-ve-serbest-agirlik-karsilastirmasi-farkli-yuklerin-ve-antrenman-tecrubesinin-set-tekrarlari-uzerine-etkisi-90396.html
... One possible reason for this uniformly higher muscle activation may be due to differences in belt squat designs. Previous studies have shown that exercises in which the weight moves along a ixed track have signi icantly less muscle activation than free weight exercises [11][12][13]. Schwanbeck, et al. [12] investigated the EMG activity of a free weight squat as compared to a Smith machine and found 43% higher muscle activation when using the free weight squat. It was surmised that the closed chain task increases knee compressive forces and stimulated a joint co-contraction. ...
... Previous studies have shown that exercises in which the weight moves along a ixed track have signi icantly less muscle activation than free weight exercises [11][12][13]. Schwanbeck, et al. [12] investigated the EMG activity of a free weight squat as compared to a Smith machine and found 43% higher muscle activation when using the free weight squat. It was surmised that the closed chain task increases knee compressive forces and stimulated a joint co-contraction. ...
... 16,17 The Free-Weights may be more beneficial than the Smith Machine squat for individuals who are looking to strengthen the plantar flexors. 18 However, it is important to point out that little is known about the effect of the RE with Free-Weights versus Machines in ankle ROM. The absence of data supports the need for additional studies in this area. ...
... The results of this study confirm that RE with free-weights may contribute to movement in multiple planes and requires more stabilization and balance. 1,18 These factors seem to be very important for increasing range of motion, functional performance, and injury prevention of the ankles. ...
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The purpose of this investigation was to compare ankle functional performance and ankle range of motion (ROM) between practitioners of resistance exercise (RE) with free-weights versus machines. Twenty-five men participated in this study. They were separated into two groups: (a) Free-weights; and (b) Machines. All subjects practiced regularly RE 5.3±0.7 d∙wk-1 and low aerobic training of 1.2±0.5 d∙wk-1 with a total time volume of 254.9±9.4 min∙wk-1. ROM measurements were taken in both ankles with a digital goniometer. Active ankle-dorsiflexion and plantar flexion range of motion were measured with subjects lying prone with an extended knee on a standard treatment table. The rising on the heel and the rising on toes were used to assess endurance of the ankle dorsiflexor and plantar flexor muscles, respectively. Ankle functional stability was assessed with the Single Leg Hop Test in both limbs. Ankle-dorsiflexion ROM showed a significant difference (Δ% left=21.1%; Δ% right=25.8%; P<0.01) between the Machines Group when compared to the Free-weights Group. Rising on the heel and rising on the toes showed no significant differences between the 2 groups (i.e., free-weights versus machines) (P>0.05). On the other hand, the Single Leg Hop Test (Δ% left=16.3%; Δ% right=15.4%; P<0.05) and number of jumps (Δ% left=27.9 %; Δ% right=26.1 %; P<0.05) recorded were lower in the Free-weights Group compared to the Machines Group. This study found a greater ankle-dorsiflexion ROM and performance during the Single Leg Hop Test in practitioners of RE with free-weights, showing a better control of sagittal plane movements.
... Cronin et al. [9] determining factors in lunge performance, they applied 1.5 times the leg length in the lunge Wurm et al. [16] found that for the lower extremity, they applied the feet distance in lunge movement as 120 cm. They stated that strength training with free weights is effective for strength and power development [2,14]. Considering the literature, it is observed that the difference between different foot widths has not been examined, although it has been chosen to perform the lunge exercise at a certain pace and leg width. ...
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The aim of this study was to determine the optimal foot distance in the isometric lunge exercise (IL) and to reveal its relationship with one repetition maximum (1-RM) squat. Twelve male athletes (Age: 22.50 ±1.98 years, Height:179.17 ± 2.21 cm, Body mass: 77.92 ± 4.75 kg) were participated in this study. Isometric lunge was applied to the participants in three different foot distance [leg length (LL), 70% of leg length (70% LL), 130% of leg length (130% LL)]. During these applications, ground reaction forces (vGRF) were measured by load cells from the front and back legs, and muscle activations were recorded by using the wireless EMG from the front leg. Vastus medialis (VM), vastus lateralis (VL), biceps femoris (BF) and semitendinosus (ST) activities were recorded for these variations of lunge exercises. As a result of these measurements, the highest force data and the most effective muscle activation were determined in 70% LL. In terms of vGRF and EMG, there was significant differences between all variations of IL (p < 0.005). There were also found significant differences between the VL and VM in the same variation of IL at third variation (p < 0.005). These significant differences were also found for the BF and ST muscles at all IL (p < 0.005). In conclusion, applied at 70% of LL, the force production of the front leg and the activation levels of the VM and VL muscles were higher than the other two applications. For the higher BF and ST, a 130% LL variation of ILs may also be recommended.
... When performed on a Smith machine, the reduced balance demands are theorised to contribute to a greater squat 1RM (i.e., 3.7%) when compared to free-weight squat 1RM (Smith machine: 129.0 kg, free-weight: 124.3 kg) [50]. This is despite greater electromyographic activity of the vastus medialis (49%), gastrocnemius (34%) and biceps femoris (26%) is observed during freeweight squats when compared to Smith machine squats [51]. Taken together, it remains unknown whether Smith machine predictions are transferrable to free-weights for lower body movements. ...
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Maximal strength can be predicted from the load-velocity relationship (LVR), although it is important to understand methodological approaches which ensure the validity and reliability of these strength predictions. The aim of this systematic review was to determine factors which influence the validity of maximal strength predictions from the LVR, and secondarily to highlight the effects of these factors on the reliability of predictions. A search strategy was developed and implemented in PubMed, Scopus, Web of Science and CINAHL databases. Rayyan software was used to screen titles, abstracts, and full texts to determine their inclu-sion/eligibility. Eligible studies compared direct assessments of one-repetition maximum (1RM) with predictions performed using the LVR and reported prediction validity. Validity was extracted and represented graphically via effect size forest plots. Twenty-five eligible studies were included and comprised of a total of 842 participants, three different 1RM prediction methods, 16 different exercises, and 12 different velocity monitoring devices. Four primary factors appear relevant to the efficacy of predicting 1RM: the number of loads used, the exercise examined, the velocity metric used, and the velocity monitoring device. Additionally , the specific loads, provision of velocity feedback, use of lifting straps and regression model used may require further consideration.
... Compound lifts, like the deadlift and squat, require trunk activation and enhance core stability [92]. Compared to stationary machine exercises, free-weight exercises rely on additional activation of the stabilizers, plantar and knee flexors, and enhanced quadriceps and knee extensor activation to enhance gait speed [93]. Biomechanical studies reveal that squatting, whether traditional, goblet squat, or box squat, provides an array of shear stresses and linear displacement on the long bones and joints through varying moment arms at the hips, knees, ankles, and lumbosacral spine (Fig. 3) requiring intense coordination and core activation for stability [94]. ...
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There are many benefits to the addition of exercise to cancer treatment and survivorship, particularly with resistance training regimens that target hypertrophy, bone mineral density, strength, functional mobility, and body composition. These goals are best achieved through a series of individualized high-intensity compound movements that mirror functional mobility patterns and sufficiently stress the musculoskeletal system. As a result of adequate stress, the body will engage compensatory cellular mechanisms that improve the structural integrity of bones and muscles, stimulate metabolism and the immune system, optimize functional performance, and minimize mechanical injury risk. The current evidence suggests that application of the above exercise principles, practiced in a safe environment under expert observation, may offer patients with cancer an effective means of improving overall health and cancer-specific outcomes. The following article poses several important questions certified exercise specialists and physicians should consider when prescribing resistance exercise for patients with cancer.
... Although no previous study has directly compared the present overhead press variations, previous papers examined the muscle excitation when different level of stabilization was required. For example, in line with the present results, posterior deltoid was more excited when shoulder press was performed standing vs. seated, irrespectively if performed with barbell or dumbbells (Saeterbakken and Fimland, 2013), or barbell vs. machine exercises (McCaw and Friday, 1994;Schwanbeck et al., 2009). A similar pattern was observed here for medial deltoid, so that less stable trajectories require more excitation. ...
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Overhead press is commonly performed to reinforce the muscles surrounding the shoulders. However, many overhead press variations can be executed, thus varying the stimuli to each muscle. Therefore, the current study compared the muscles excitation during overhead press performed with the barbell passing in front or behind the head or using a shoulder press machine. Eight competitive bodybuilders performed in random order front (front-BMP) or back barbell military press (back-BMP), and front (front-MSP) with neutral handgrip or back machine shoulder press (back-MSP). Normalized surface electromyographic root mean square (RMS) of anterior, medial and posterior deltoid, upper trapezius, pectoralis major and triceps brachii was recorded during both the ascending and descending phases. During the ascending phase, anterior deltoid showed greater RMS in back-BMP than back-MSP [ES: 1.42, (95% confidence interval 0.32/2.51)]. Medial deltoid showed greater RMS in back-BMP than front-BMP [ES: 3.68 (2.07/5.29)], and back-MSP [ES: 7.51 (4.73/10.29)]. Posterior deltoid showed greater RMS in back-BMP than front-BMP [ES: 9.00 (5.73/12.27)]. Pectoralis major showed greater RMS in front-BMP than back-BMP [ES: 3.11 (1.65–4.56)] and in front-MSP than back-MSP [ES: 20.52 (13.34/27.70)]. During the descending phase, anterior deltoid was more excited in back-BMP compared to front-BMP [ES: 7.66 (4.83/10.49). Medial deltoid showed greater RMS in back-BMP than front-BMP [ES: 4.56 (2.70/6.42)]. Posterior deltoid showed greater RMS in back-BMP than front-BMP [ES: 8.65 (5.50/11.80)]. Pectoralis major showed greater RMS in front-BMP than back-BMP [ES: 4.20 (2.44/5.95)]. No between-exercise difference was observed for upper trapezius. Performing back overhead press enhances the excitation of medial and posterior and partly anterior deltoid, while front overhead favors pectoralis major. Overhead press performed using barbell excites muscles more than using machine to stabilize the trajectory of the external load. Different variations of overhead press appear to provide different stimuli to the shoulder muscles and may be used accordingly during the training routine.
... Although free weight exercises are often recommended, because they require greater motor control and muscle recruitment demand (Schwanbeck et al., 2009), recent studies demonstrated that training with free weights or machines resulted in similar increases in muscle strength in young people (Schwanbeck et al., 2020). To the best of our knowledge, only one study has investigated hip abductors activation using hip abduction machines. ...
Article
Introduction Changes in the lower extremities’ biomechanics are associated with gluteus medius (GMed) weakness and increased tensor fascia latae (TFL) activation. Objective To determine which exercises produce greater GMed activity while minimizing TFL activation during the concentric and eccentric phases of three single-joint strengthening exercises. Design Controlled laboratory study. Setting Laboratory. Participants Eleven males (age: 29.18 ± 4.51 years; body mass: 84.01 ± 14.48 kg; height: 1.74 ± 0.07 m; body fat: 16.34 ± 3.33%). Main outcome measures GMed and TFL activation and activation ratio while performing ten maximal repetitions of three exercises: side-lying hip abduction (SLHA); clamshell (CLAM) and hip abductor machine (HAM). Results GMed activation was greater than TFL in all exercises in both concentric and eccentric phases. There were no differences in GMed activation between the three exercises in both phases. TFL activation was greater in SLHA compared to HAM and CLAM during both phases. In both concentric and eccentric phases, GMed:TFL ratio was greater in HAM compared to CLAM and SLHA. Conclusions GMed had increased activation compared to TFL in all analyzed exercises. Considering GMed:TFL ratio, if the goal is to preferentially activate GMed while minimizing TFL activation, the hip abductor machine seems to be the best exercise.
... Results of this study show that VR can be effectively used together with free weight exercise protocols and increase performance in such exercises. We believe that the results of this study are useful from an applied perspective, given that free weight exercising is often recommended over machine-based weight lifting (Schick et al., 2010;Schwanbeck et al., 2009), and that the number of exercise repetitions is an ecologically valid measure, directly relevant to real training protocols. ...
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Virtual Reality (VR) technology can be used to influence performance on endurance exercises. In this study, we focused on manipulating perception of own-body strength by exercising in VR as a muscular avatar. In this repeated-measure study, twenty-nine participants performed biceps curl exercise in a maximum repetitions protocol, up to exhaustion. The exercise was done either in VR as a muscular avatar, or without VR, in front of the mirror. Dependent variables were the number of exercise repetitions and self-reported exertion. We also controlled blood glucose level, perceived weight of the barbell and level of embodiment. Participants performed significantly more biceps curl repetitions in the VR condition (Z = -2.05, p < .05) with an effect size of d = 0.36. The self-reported effort did not differ significantly between conditions. The results of this study may have an applied significance since number of exercise repetitions is an ecologically valid measure, directly relevant to real training protocols.
... As noted earlier, a benefit of high-intensity RET is the ability to maximally recruit the majority or all the fibers of a targeted muscle group (Rader et al., 2017b), which is somewhat offset using machines. Although some previous research has demonstrated that short-term (8-week) RET training with free weights or machines induces similar increases in muscle mass and strength (Schwanbeck et al., 2020), free weight usage has resulted in greater electromyography muscle activation (McCaw and Friday, 1994;Schwanbeck et al., 2009), and greater increases in circulating testosterone concentrations (Schwanbeck et al., 2020) than RET using machines. As most improvements in muscle strength during the first phases of training are due to neural adaptations rather than muscle hypertrophy (Moritani and deVries, 1979;Sale, 1988), it is not surprising that increases in muscle mass during short-term RET are similar with free weights and machines (Schwanbeck et al., 2020). ...
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Muscle quality (MQ), defined as the amount of strength and/or power per unit of muscle mass, is a novel index of functional capacity that is increasingly relied upon as a critical biomarker of muscle health in low functioning aging and pathophysiological adult populations. Understanding the phenotypical attributes of MQ and how to use it as an assessment tool to explore the efficacy of resistance exercise training interventions that prioritize functional enhancement over increases in muscle size may have implications for populations beyond compromised adults, including healthy young adults who routinely perform physically demanding tasks for competitive or occupational purposes. However, MQ has received far less attention in healthy young populations than it has in compromised adults. Researchers and practitioners continue to rely upon static measures of lean mass or isolated measures of strength and power, rather than using MQ, to assess integrated functional responses to resistance exercise training and physical stress. Therefore, this review will critically examine MQ and the evidence base to establish this metric as a practical and important biomarker for functional capacity and performance in healthy, young populations. Interventions that enhance MQ, such as high-intensity stretch shortening contraction resistance exercise training, will be highlighted. Finally, we will explore the potential to leverage MQ as a practical assessment tool to evaluate function and enhance performance in young populations in non-traditional research settings.
... Thus, strength and conditioning coaches and fitness professional have a variety of equipment to choose from when deciding which equipment to purchase or to prescribe. Debate about what type of equipment to prescribe in training programs often centers around the idea of optimal physiological effectiveness (5,13,16). In studies on free-weight equipment versus stationary machines, researchers have often aimed to determine which equipment leads to the greatest improvements in muscle strength or other performance outcomes (5,6,14,27). ...
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Nuzzo, JL. Content analysis of patent applications for strength training equipment filed in the United States before 1980. J Strength Cond Res XX(X): 000-000, 2021-Strength training history is an emerging academic area. The aim of the current study was to describe quantitively the history of inventions for strength training equipment. Content analysis was conducted of patent applications for strength training equipment filed with the U.S. Patent and Trademark Office before 1980. Applications were identified using relevant keyword searches in Google Patents. A total of 551 patent applications were analyzed. The earliest application identified was filed in 1860. Applications never exceed 6 per year until 1961 after which applications increased substantially, with a peak of 54 in 1979. Men invented 98.7% of all strength training devices. Lloyd J. Lambert, Jr. was the most prolific inventor, with 10 inventions. Types of inventions included mobile units (34.5%), stationary machines (27.9%), dumbbells (16%), racks or benches (8.0%), barbells (6.7%), and Indian clubs (3.8%). Common features included seats or benches (18.7%), cable-pulley systems (15.1%), weight stacks (8.2%), weight trays (4.5%), and cams (2.2%). Common types of resistance included weights or plates (33.2%), springs (11.6%), friction (9.1%), elastic bands (5.3%), and hydraulic (3.8%). Proposed invention benefits included adjustable resistance (37.4%), inexpensive (36.1%), simple to use (32.8%), compact design or easy storage (27.0%), multiple exercise options (26.1%), safety and comfort (25.4%), effectiveness (23.6%), portability (20.5%), adjustable size (15.8%), sturdiness or durability (15.8%), home use (13.6%), and light weight (13.6%). Certain aspects of strength training equipment have evolved over time. However, overall purposes and benefits of inventions have remained constant (e.g., affordability, convenience, personalization, safety, and effectiveness).
... Despite numerous criticisms regarding Smith-machines and their transferability to applied settings, most literature in this space continues to employ them. Research suggests that mechanical outputs such as take-off velocity (directly related to peak velocity), maximum load lifted, and electromyographical muscle activity differ when performing Smith-machine exercises compared to free-weight, suggesting that the generalizability of this research to broader contexts using free-weight exercise is limited [37][38][39]. Future research should therefore seek to elucidate the predictive validity of approaches most represented in practice, such as free-weight upper and lower body exercises. ...
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The study aim was to compare different predictive models in one repetition maximum (1RM) estimation from load-velocity profile (LVP) data. Fourteen strength-trained men underwent initial 1RMs in the free-weight back squat, followed by two LVPs, over three sessions. Profiles were constructed via a combined method (jump squat (0 load, 30–60% 1RM) + back squat (70–100% 1RM)) or back squat only (0 load, 30–100% 1RM) in 10% increments. Quadratic and linear regression modeling was applied to the data to estimate 80% 1RM (kg) using 80% 1RM mean velocity identified in LVP one as the reference point, with load (kg), then extrapolated to predict 1RM. The 1RM prediction was based on LVP two data and analyzed via analysis of variance, effect size (g/), Pearson correlation coefficients (r), paired t-tests, standard error of the estimate (SEE), and limits of agreement (LOA). p < 0.05. All models reported systematic bias < 10 kg, r > 0.97, and SEE < 5 kg, however, all linear models were significantly different from measured 1RM (p = 0.015 <0.001). Significant differences were observed between quadratic and linear models for combined (p < 0.001; = 0.90) and back squat (p = 0.004, = 0.35) methods. Significant differences were observed between exercises when applying linear modeling (p < 0.001, = 0.67–0.80), but not quadratic (p = 0.632–0.929, = 0.001–0.18). Quadratic modeling employing the combined method rendered the greatest predictive validity. Practitioners should therefore utilize this method when looking to predict daily 1RMs as a means of load autoregulation.
... Although both functional movements (any type of training that is performed with purpose to enhance a certain movement or activity) (48) and traditional resistance training improve muscle hypertrophy, decrease fat mass, and improve strength (26), functional resistance training has been shown to provide additional benefits regarding dynamic agility, balance, and gait function, especially in older women (25). The inclusion of free-weight versus machine exercises may provide more well-rounded benefits in terms of strengthening plantar flexors, knee flexors, and knee extensors to aid in injury prevention and enhanced functional mobility (72). Furthermore, squat and deadlift resistance exercises provide additional trunk muscle activation maximizing core stability training compared with common core exercises (37). ...
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Rosenberg, J, Hyde, PN, Yancy, WS, Ford, KM, and Champ, CE. Quantity of resistance exercise for breast cancer patients: does the dose match the objective? J Strength Cond Res 35(5): 1467-1476, 2021-There is currently a lack of consensus as to what defines exercise and resistance training in the cancer setting and whether current studies comply with exercise guidelines. This study aimed to quantify the available research studies using resistance training exercise interventions in the breast cancer setting for future clinical trial utilization. We systemically reviewed all available resistance exercise studies during and after breast cancer treatment in an attempt to quantify to the prescribed dose and whether regimens aligned with general exercise guidelines to improve functional mobility, body composition, and metabolic function. They were then compared with recommendations set forth by the national committees that create evidence-based exercise guidelines. Fifty studies met the initial criteria, with 35 meeting analysis criteria for evaluation. Fifteen studies evaluated an exercise regimen during cancer treatment, and 20 evaluated a regimen after treatment. The average adherence rates were 84% for all studies. Only 23 studies listed specific exercises used within the protocol. Most exercise regimens relied on open chain movements and machine exercises. Around half of studies met criteria to achieve hypertrophy, and 66% met American College of Sports Medicine exercise guidelines for cancer patients. A minority of breast cancer studies implementing a resistance training exercise regimen prescribed a regimen or specific dose that follows general exercise guidelines. This study highlights a potential deficiency in exercise programs designed for patients with breast cancer, and these findings should be considered in future study design.
... Based on the participants' RPE scores during the familiarisation trial, a starting weight which was estimated to score 5 on the RPE scale was determined by the researcher. Participants were allocated at least four minutes' rest period before the next attempt to allow sufficient recovery [59]. A 5-RM attempt was confirmed when participants provided an RPE of 10 referring to "very, very heavy-maximum exertion". ...
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Cross-sectional studies in younger adults have demonstrated a positive association between energy intake (EI) and fat-free mass (FFM), with this relationship seemingly mediated by resting metabolic rate (RMR). Establishing a causal effect longitudinally would be prudent in older adults suffering from loss of appetite. We investigated the effects of FFM on RMR, appetite and EI in 39 healthy older adults (age: 66 ± 4 years, BMI: 25.1 ± 3.5 kg∙m2) assigned to either 12-week resistance training + protein supplementation group (RT + PRO) or control group (CON). Body composition, subjective appetite, leptin, insulin, RMR and laboratory-measured ad libitum EI were measured at baseline, weeks 6 and 12 of the intervention, while daily EI at baseline and week 12. FFM (+1.2 kg; p = 0.002), postprandial subjective appetite (+8 mm; p = 0.027), ad libitum EI (+119 kcal; p = 0.012) and daily EI (+133 kcal; p = 0.010) increased from baseline to week 12 in the RT + PRO. RMR, fasted subjective appetite, leptin and insulin concentrations remained unchanged (all p > 0.05). The increases ad libitum EI correlated with increases in FFM (r = 0.527, p = 0.001), with 54% of the change in EI attributed to FFM changes. In conclusion, FFM increases were associated with an increased ad libitum EI and postprandial appetite in older adults.
... Push-up: pectoralis major, anterior deltoid, triceps brachii, rectus abdominis, and external obliques (15,32,35); Plank: rectus abdominis, internal and external obliques, and erector spinae (7,19,31); Squat: gluteus maximus, gluteus medius, quadriceps group, hamstrings group, adductor longus, gastrocnemius, and soleus (13,27); ...
... A potential explanation for this finding is that squatting requires balancing on two feet with substantial engagement of stabilizing and core musculature, such as the abdominals and back. Research on muscle activation has also shown that free weight exercise results in a greater muscle activation than machine exercise, likely by inducing a larger overall muscle mass involvement than similar machine-based weight exercises [50]. These findings are supported by studies in junior Olympic-style weightlifters [16]. ...
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Exercise has been proposed to increase serum testosterone concentrations. The analysis of existing literature demonstrates a large degree of variability in hormonal changes during exercise. In our manuscript, we summarized and reviewed the literature, and concluded that this variability can be explained by the effect of numerous factors, such as (a) the use of different types of exercise (e.g., endurance vs. resistance); (b) training intensity and/or duration of resting periods; (c) study populations (e.g., young vs. elderly; lean vs. obese; sedentary vs. athletes); and (d) the time point when serum testosterone was measured (e.g., during or immediately after vs. several minutes or hours after the exercise). Although exercise increases plasma testosterone concentrations, this effect depends on many factors, including the aforementioned ones. Future studies should focus on clarifying the metabolic and molecular mechanisms whereby exercise may affect serum testosterone concentrations in the short and long-terms, and furthermore, how this affects downstream mechanisms.
... We reported that muscles of the lower limb have been investigated more than trunk muscles, i.e. hamstring and quadriceps activation data were reported more than any other muscle groups (Clark et al. 2012). Furthermore, we and others have investigated trunk stabilizer muscle activation in the back squat and established that activation is greater in concentric compared to eccentric phase and activation increases with increases in external load (Hamlyn et al. 2007;Nuzzo et al. 2008;Schwanbeck et al. 2009;Comfort et al. 2011;Aspe and Swinton 2014;Clark et al. 2016Clark et al. , 2020. We also showed that trunk muscle activation in loaded barbell squat was highest in the deepest range of both eccentric and concentric phases (Clark et al. 2020). ...
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Purpose In this study we measured neural activation (EMG) in four trunk stabilizer muscles and vastus lateralis (VL) in trained and novice participants during a set of squat repetitions to volitional fatigue at 85% 1RM. Methods Forty males were recruited into two groups, novice (NG: n = 21) and experienced (EG: n = 19), according to relative squat 1RM. Participants were tested twice to: (1) determine squat 1RM, and (2) complete a single set of repetitions to volitional fatigue at 85% 1RM. Relative squat 1RM; NG < 140% body mass, EG > 160% body mass. Neuromuscular activation was measured by EMG for the following: rectus abdominus (RA), external oblique (EO), lumbar sacral erector spinae (LSES), upper lumbar erector spinae (ULES) and VL in eccentric and concentric phase. Completed repetitions, RPE and EMG in repetition 1 and at 20, 40, 60, 80 and 100% of completed repetitions were analysed. Results No group differences were found between number repetitions completed and RPE in repetitions to volitional fatigue at 85% 1RM. Neuromuscular activation increased significantly in all muscle groups in eccentric and concentric phase apart from RA in the eccentric phase. Trunk neuromuscular activation was higher in NG compared to EG and this was significant in EO, LSES and ULES in eccentric phase and LSES in the concentric phase. VL activation increased in both phases with no group differences. Conclusion Trunk neuromuscular activation increases in a fatiguing set of heavy squats regardless of training status. Increased back squat strength through training results in lower neuromuscular activation despite greater absolute external squat loads.
... The use of a Smith machine with an inclined rail was a unique feature of this study for measurements of knee loads because prior studies using Smith machines for squats were either limited to the analysis of 1-RM loads [35] or to the assessment of muscle activation [36]. The use of this particular equipment is beneficial as it can help inform exercise prescription for recreational use of strength training, maintenance of health and rehabilitation. ...
Article
BACKGROUND: Comparison of knee loads on a Smith machine, which utilised in for maintenance of health and rehabilitation, has not been attempted. OBJECTIVE: This study compared lower limb muscle and knee joint forces during front and back squats performed on a Smith Machine. METHODS: Eleven participants performed front and back squats with loads at 40%, 60% and 80% of their back squat 1-RMs. Ground reaction forces and three-dimensional full body motion were collected and used for modelling lower limb muscle and knee joint forces. RESULTS: Larger loads increased tibiofemoral compressive force during back squat at 80% compared to 40% (p< 0.01; d= 1.58) and to 60% (p< 0.01; d= 1.37). Patellofemoral compressive (p= 0.96) and tibiofemoral shear forces (p= 0.55) were not influenced by external load or type of squat. Gluteus medius and minimus produced more force at 80% compared to 60% (p= 0.01; d= 1.10) and to 40% (p< 0.01; d= 1.87) without differences for other muscles (p= 0.09–0.91). CONCLUSIONS: Greater external load was associated with increase in gluteus medius and minimus force and with increased tibiofemoral compressive force without effects on tibiofemoral shear force, patellofemoral compressive force or other lower limb muscle forces.
... A notable higher trunk muscle activity has been observed, especially during free weight lifting compared to machines (Behm & Colado Sanchez, 2013;Schwanbeck et al., 2009). Aspe et al (2014) showed a higher level of trunk muscle activity generated during the overhead squat compared to performing back squats. ...
Article
Squats are considered a useful basic exercise for trunk muscle activation. To gain knowledge about trunk muscle activity patterns depending on the barbell position in beginners, we examined squats with low weights in the back, front, and overhead position. Methods: Twelve healthy adults (6 women/6 men, age: 29.1 (SD 8.0) y, height: 173.4 (6.9) cm, body mass: 70.1 (9.1) kg) randomly performed the three barbell squats in normal and in forefoot standing. Surface electromyography from external (EO) and internal oblique, rectus abdominis, and erector spinae (ES) was recorded. The centre of pressure path length (CoP) and the motion of the lumbar spine were captured. Results: The overhead squat revealed the highest percent muscle activity, where EO (p = 0.009) and ES (p = 0.03) showed the greatest activity. Forefoot standing did not change overall trunk muscle activities (.05< Hedges' g <.29, 0.17 < p < 0.95) although longer CoP path length (.45 < g < 1.3, p < 0.05) was measured. Conclusions: Squat exercises with low weight are useful to activate trunk muscles. Activity increases with the difficulty of the squat by frontal or overhead loading, but not by standing on the forefoot. The low weighted squat can target well core muscle activity in training with beginners or in rehabilitation.
... Diversos movimentos e atividades esportivas exigem os músculos dos quadríceps(26) e as máquinas guiadas de TF proporcionam ganhos de força isolados, além de possibilitarem a aplicação de maior carga interna de trabalho e maior segurança em comparação com exercícios realizados com pesos livres (27,28). A cadeira extensora é uma excelente opção em programas de treinamento com o objetivo de ganhos de força nos extensores de joelhos. ...
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Introdução: Praticantes de musculação, de todos os níveis, buscam estratégias eficazes e eficientes para otimizar o treinamento de força. Nesse contexto, o alongamento estático nos músculos antagonistas como aquecimento parece proporcionar melhorias no desempenho de força nos músculos agonistas. Objetivo: Avaliar o efeito agudo no desempenho de força de quadríceps, no movimento de extensão de pernas, na cadeira extensora, em resposta ao alongamento estático dos músculos antagonistas (isquiotibiais). Métodos: Estudo experimental, com amostra por conveniência, do qual participaram 14 homens, com experiência em TF. Foram aplicados teste e reteste de 10 repetições em carga máxima (10RM). Antes do treinamento de força, foram realizaram dois protocolos com intervalo de 48-72 h, nos quais, durante o aquecimento foram aplicados dois protocolos distintos: a) O tradicional (TR) sem alongamento estático dos músculos antagonistas; e b) com alongamento estático dos isquiotibiais (AEI), os antagonistas aos músculos quadríceps. Resultados: Não houve diferenças significativas no volume total de trabalho (VTT) entre os protocolos TR (1727,86±697,05Kg) e AEI (1782,14±719,21Kg). No protocolo TR, foram encontradas diferenças significativas no número de repetições das 1ª (9,93±0,27; p=0,001) e 2ª (9,21±0,97; p=0,030) séries em relação ao número de repetições da 3ª série (8,21±1,25). No protocolo AEI, foram encontradas diferenças significativas no número de repetições da 1ª (10,14±0,36) série em relação ao número de repetições das 2ª (9,14±1,10; p=0,010) e 3ª (8,86±1,41; p=0,012) séries. Conclusão: Em conclusão, realizar 40s de alongamento estático nos isquiotibiais não parece prejudicar o desempenho muscular na cadeira extensora.
... The vastus medialis had lower muscle activity in the Smith-machine foot-backwards condition when compared to the free-weight variations. This finding coincides with Schwanbeck, Chilibeck, and Binsted [25], who also found greater EMG activity for vastus medialis free-weight squats when compared to the Smith-machine squat. However, doing squats in a Smith machine provides a more stable surface owing to a closed vertical bar path. ...
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In this paper, we explore the use of numerical optimization techniques to synthesize realistic human-like squat motions. For this purpose, a two-step optimization-based synthesis scheme, inspired by whole-body controllers from robotics, is proposed. In step I, a reduced set of physically-relevant criteria is optimized to produce the state and torque patterns with a joint-actuated model. Afterwards, muscle activities are computed in step II with a muscle-actuated model. To validate the approach, the synthesized kinetic and muscle activities of two squat strategies obtained through the scheme are analyzed and compared to captured movement and electromyographic data. The outcome shows that it is feasible to synthesize human-like squats without motion capture data while exhibiting several main features of the motor function strategies. However, disparities related to the simple modeling of the actuators are observed.
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It is difficult to draw conclusions about the effect of resistance exercises on information processing speed and inhibitory control from previous studies due to possible underestimations of maximal strength and the lack of information on the intervention programs. To address this issue, a familiarization of resistance exercise was introduced before the strength test, and the repetition-to-fatigue method was used to calculate the 1RM (one repetition max). A two-arm RCT was conducted to evaluate the cognitive effect of resistance exercise. Male adults aged 50–65 years old performed a single bout of multiple joint, structural barbell resistance exercises (back squat, press, and deadlift) with 75% 1RM * 5 repetitions * 3 sets with 2–3 min rest between sets and exercises or a stretching exercise session (active-control intervention). This type of resistance exercise improved the information processing speed measured by Stroop task reaction time (t(23) = − 2.313, p = .030, M = − 16 ms, 95% CI [− 30, − 2]) and decreased the conflict-related neural activity measured by event-related potential N2b in both congruent (t(20) = 2.674, p = .015, M = 2.290 μv, 95% CI [0.504, 4.075]) and incongruent (t(20) = 2.851, p = .018, M = 2.291 μv, 95% CI [0.439, 4.142]) conditions. Resistance exercise significantly improved information processing speed and decrease conflict-related neural activity, but did not change inhibitory control in older adults compared to active control. Trial registration: NCT04534374 (01/09/2020).
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Research in instability has focused on the analysis of muscle activation. The aim of this systematic review was to analyse the effects of unstable devices on speed, strength and muscle power measurements administered in the form of controlled trials to healthy individuals in adulthood. A computerized systematic literature search was performed through electronic databases. According to the criteria for preparing systematic reviews PRISMA, nine studies met the inclusion criteria. The quality of the selected studies was evaluated using STROBE. The average score was 14.3 points, and the highest scores were located in ‘Introduction’ (100%) and ‘Discussion’ (80%). There is great heterogeneity in terms of performance variables. However, instability seems to affect these variables negatively. The strength variable was affected to a greater degree, but with intensities near to the 1RM, no differences are observed. As for power, a greater number of repetitions seems to benefit the production of this variable in instability in the upper limb. Instability, in comparison to a stable condition, decreases the parameters of strength, power, and muscular speed in adults. The differences shown are quite significant in most situations although slight decreases can be seen in certain situations.
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Featured Application: The Intelligent Motion Lifter is a new mechatronic strength training device that allows safe and effective strength training with supramaximal loads. Abstract: Eccentric muscular work plays a large role in alpine ski racing. Training with supramaximal eccentric loads (SME) is highly effective to improve eccentric strength but potentially dangerous. Most SME training devices do not allow the athlete to move a barbell freely as they would when performing conventional barbell training. The Intelligent Motion Lifter (IML) allows for safe SME training with a free barbell and no spotters. The IML can be used for free barbell training: a spotter for normal training, eccentric only, concentric only, and squat jumps. It is also a training and testing device for isokinetic and isometric exercise. This commentary addresses the necessity of eccentric training for elite alpine ski racers, the development of the IML and its use in training.
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The purpose of this study was to compare the reaction forces, power and the kinematics of the center of mass (CM) during the performance of jump squats using the Smith machine (SM) and the free weight (FW). In this study participated twenty-four athletes with experience in jumping activities and training with loads. In addition to a Smith machine, a Dinascan / IBV force platform has been used at 500 Hz. After obtaining the maximum load for each participant (1RM), the components of the reaction force (FR (X) and FR (Y)) were recorded in three load levels, with respect to their corresponding 1RM (30 %, 50% and 70%). The kinematics of the CM was obtained from the integration of the acceleration with respect to time after dividing the net force (FN) by the mass of the system (m). From the analysis of the performance times and the reaction forces, it is suggested that the FW situation would be more suitable to look for a real approach to the competition, being a movement that produces a greater postural control. The SM situation reduces the execution time and increases the momentum developed during the propulsive phase, which suggests that it could be more suitable for training the development of force at high speeds of concentric contraction.
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The objective of this study was to determine differences in isometric force output, muscle activation (interpolated twitch technique), and electromyographic activity of the quadriceps, plantar flexors (PF), and their antagonists under stable and unstable conditions. Instability in subjects was introduced by making them perform contractions while seated on a "Swiss ball." Eight male subjects performed unilateral leg extensor (LE) and PF contractions while seated on a bench (LE), chair (PF), or a ball. Unstable LE and PF forces were 70.5 and 20.2% less than their stable counterparts, respectively. Unstable quadriceps and PF activation averaged 44.3 and 2.9% less than activation under stable conditions. Unstable antagonist/agonist ratios were 40.2 and 30.7% greater than stable ratios in the LE and PF protocols, respectively. The greater decrements with LE can be attributed to the instability of only 2 points of floor contact, rather than 3 points of floor contact as with the PF. Swiss balls may permit a strength training adaptation of the limbs, if instability is moderate, allowing the production of overload forces.
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The objective of this study was to determine differences in electromyographic (EMG) activity of the soleus (SOL), vastus lateralis (VL), biceps femoris (BF), abdominal stabilizers (AS), upper lumbar erector spinae (ULES), and lumbo-sacral erector spinae (LSES) muscles while performing squats of varied stability and resistance. Stability was altered by doing the squat movement on a Smith machine, a free squat, and while standing on two balance discs. Fourteen male subjects performed the movements. Activities of the SOL, AS, ULES, and LSES were highest during the unstable squat and lowest with the Smith machine protocol (p < 0.05). Increased EMG activity of these muscles may be attributed to their postural and stabilization role. Furthermore, EMG activity was higher during concentric contractions compared to eccentric contractions. Performing squats on unstable surfaces may permit a training adaptation of the trunk muscles responsible for supporting the spinal column (i.e., erector spinae) as well as the muscles most responsible for maintaining posture (i.e., SOL).
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Many strength and conditioning professionals design and implement resistance training programs that involve both free-weights and weight machines. These programs are often designed in an attempt to improve strength, power, and ultimately athletic performance. The benefits of both modalities of resistance training are often discussed by athletes, coaches, athletic trainers, and sport scientists. In these discussions, there are many differing opinions about which modality or combination of modalities produces optimal sports performance gains. The purpose of this roundtable is to discuss several issues related to the use of free-weight and machine modalities in an athletic setting.
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This study evaluated the effect of the gastrocnemius and soleus muscles on dynamic knee stability by studying the effect of passive calf muscle loading on anterior tibial translation in normal and anterior cruciate ligament (ACL) deficient knees. Anterior tibial translation was measured bilaterally in 12 anesthetized patients with unilateral ACL-deficient knees using a KT-1000 arthrometer. An ankle-foot orthosis was used to passively dorsiflex the ankle and generate tension in the calf muscles. As the ankle flexion angle was progressively changed from 30 degrees plantar flexion to 10 degrees dorsiflexion, anterior tibial translation decreased 43% and 37% with manual maximum force in normal and ACL-deficient knees, respectively (P < .0001). These findings suggest that the calf muscles may function as dynamic knee stabilizers. Anterior tibial translation also was measured in four cadaver knees. Significant decreases were seen in anterior tibial translation with progressive ankle dorsiflexion in ACL-intact specimens and after the ACL had been cut (P < .05). This effect persisted when the gastrocnemius muscle was cut, but was lost when the soleus muscle was released. The data suggest that the soleus muscle may play a role in dynamically stabilizing the knee.
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This paper examines the postulate that an important function of the activity of antagonist muscle groups is to modulate mechanical impedance. Some biomechanical modeling and analyses are presented leading to a prediction of simultaneous activation of antagonist muscles in the maintenance of upright posture of the forearm and hand. An experimental observation of antagonist coactivation in this situation is presented.