Content uploaded by Brad J Schoenfeld
Author content
All content in this area was uploaded by Brad J Schoenfeld on Oct 09, 2017
Content may be subject to copyright.
A preview of the PDF is not available
Influence of Resistance Training Frequency on Muscular Adaptations in Well-Trained Men
Abstract and Figures
The purpose of this study was to investigate the effects of training muscle groups 1 day per week using a split-body routine versus 3 days per week using a total-body routine on muscular adaptations in well-trained men. Subjects were 20 male volunteers (height = 1.76 ± 0.05 m; body mass = 78.0 ± 10.7 kg; age = 23.5 ± 2.9 years) recruited from a university population. Participants were pair-matched according to baseline strength and then randomly assigned to 1 of 2 experimental groups: a split-body routine (SPLIT) where multiple exercises were performed for a specific muscle group in a session with 2-3 muscle groups trained per session (n = 10), or; a total-body routine (TOTAL), where 1 exercise was performed per muscle group in a session with all muscle groups trained in each session (n = 10). Subjects were tested pre- and post-study for 1 repetition maximum strength in the bench press and squat, and muscle thickness of forearm flexors, forearm extensors, and vastus lateralis. Results showed significantly greater increases in forearm flexor muscle thickness for TOTAL compared to SPLIT. No significant differences were noted in maximal strength measures. The findings suggest a potentially superior hypertrophic benefit to higher weekly resistance training frequencies.
Figures - uploaded by Brad J Schoenfeld
Author content
All figure content in this area was uploaded by Brad J Schoenfeld
Content may be subject to copyright.
... 12 Bu nedenle antrenman sıklığı (bir kas grubunun 1 haftada kaç kez çalıştırıldığı), kas kütlesi ve gücünü özellikle antrenmanlı bireylerde artırmak için etkili bir yöntem olarak önerilmiştir. 13,14 DE sıklığı, genellikle haftalık olarak tanımlanan belirli bir zaman aralığındaki antrenman sayısıyla ifade edilir. Sıklık, haftalık antrenman oturumlarıyla daha iyi açıklanabilir; özellikle aynı kas grubunun haftada kaç kez çalıştırıldığı dikkate alınarak değerlendirilebilir. ...
... Bu, bir antrenman oturumunda birden fazla egzersiz ve setin belirli bir kas grubu için yapılmasıyla elde edilir. 13,15 DE sırasında setlerin, tekrarların ve kaldırılan ağırlığın manipülasyonu (genellikle maksimum tekrarlara göre bir yüzde olarak ifade edilir) nöromusküler adaptasyonları belirler. Tipik bir güç antrenmanı, düşük hacimli (3-5 set ≤6 tekrar) ve yüksek yüklerin kullanıldığı antrenmanlar [≥%85 1 tekrar maksimal (1TM)] olarak ifade edilir. ...
... Bu araştırmacılar, bir kas grubuna haftada 1 veya 3 antrenman sıklığı uygulamanın, her iki durumda da maksimum kuvveti önemli ölçüde artırdığını ve antrenman sıklığı arasında belirgin bir fark olmadığını tespit etmişler- dir. 13 Ancak McLester ve ark., 12 haftalık bir antrenman sürecinin sonunda, düşük sıklıkta antrenmanın yüksek sıklıkla yapılan antrenmana göre güç kazanımının 2/3 oranında daha az olduğunu bulmuşlardır. 30 Bunun yanında, Colquhoun ve ark., eşit hacimli antrenmanlarda, haftada 6 ve 2 kez antrenman yapan gruplar arasında benzer kuvvet kazanımları olduğunu gözlemlemişlerdir. ...
... Thomas and Burns conclude that higher training volume may be necessary to exceed lean tissue mass and strength gains presented in their study. This conclusion agrees with others that hypothesized that resistance training volume and associated frequency may be a significant determiner of outcomes especially hypertrophy (9,24,25). These results demonstrate the need for research assessing the impact of high volume and frequency RT on lean tissue mass and strength acquisition. ...
... Resistance exercise has consistently demonstrated an ability to improve the strength and size of skeletal muscle. Investigators have hypothesized that high volume resistance exercise may improve the adaptive response and that muscle hypertrophy occurs during the early weeks of commencing RT (4,6,21,25,27,30). However, published research examining early timeline adaptations is limited especially research that involves trained participants. ...
... For example, similar gains in muscle mass and strength performance have been reported after split and full-body routines between untrained (10,13,25) and trained (12,22) people. By contrast, other studies reported that full-body routines may be more effective at improving cross-sectional area than split routines (34,39) . Conversely, Bartolomei et al. (2) found opposite results, reporting that the full-body training paradigm may be more appropriate for improving maximal strength, whereas a split routine training may be more optimal for stimulating muscle growth in experienced resistance-trained men. ...
... Although all studies included in this meta-analysis used valid and reliable methods for quantifying muscle mass, different authors employed methods with varying levels of precision. Ultrasound was the most widely used method, employed by up to 5 studies (2,9,22,34,35,39) followed by dual-energy X-ray absorptiometry (DXA), which was used by 3 studies (5,10,12), anthropometry, used in 2 studies (7,13), and bioelectrical impedance, used only by Pedersen et al. (25). ...
Ramos-Campo, DJ, Benito-Peinado, PJ, Caravaca, LA, Rojo-Tirado, MA, and Rubio-Arias, JÁ. Efficacy of split versus full-body resistance training on strength and muscle growth: a systematic review with meta-analysis. J Strength Cond Res XX(X): 000–000, 2024—No previous study has systematically compared the effect of 2 resistance training routines commonly used to increase muscle mass and strength (i.e., split [Sp] and full-body [FB] routines). Our objective was to conduct a systematic review and meta-analysis following PRISMA guidelines to compare the effects on strength gains and muscle growth in healthy adults. 14 studies (392 subjects) that compared Sp and FB routines in terms of strength adaptations and muscle growth were included. Regarding the effects of the Sp or FB routine on both bench press and lower limbs strength, the magnitude of the change produced by both routines was similar (bench press: mean difference [MD] = 1.19; [−1.28, 3.65]; p = 0.34; k = 14; lower limb: MD = 2.47; [−2.11, 7.05]; p = 0.29; k = 14). Concerning the effect of the Sp vs. FB routine on muscle growth, similar effects were observed after both routines in the cross-sectional area of the elbow extensors (MD = 0.30; [−2.65, 3.24]; p = 0.84; k = 4), elbow flexors (MD = 0.17; [−2.54, 2.88]; p = 0.91; k = 5), vastus lateralis (MD = −0.08; [−1.82, 1.66]; p = 0.93; k = 5), or lean body mass (MD = −0.07; [−1.59, 1.44]; p = 0.92; k = 6). In conclusion, the present systematic review and meta-analysis provides solid evidence that the use of Sp or FB routines within a resistance training program does not significantly impact either strength gains or muscle hypertrophy when volume is equated. Consequently, individuals are free to confidently select a resistance training routine based on their personal preferences.
... This recommendation is in accord with other reviews and association recommendations, which provide typical minimum recommendation for RT weekly frequency of two to three times per week in order to achieve significant increases in muscle strength, endurance, and hypertrophy [19,25,26,30,49,51,52]. Multiple weekly RT sessions are often reported to provide greater positive strength and endurance adaptations than fewer sessions; 4 > 2 [53], 3 > 1 [54], 5 > 1 [55,56], which would suggest that greater RT volumes may be more effective. However, the literature is not unanimous. ...
... Hence, for the previously sedentary individual, multiple RT sessions per week may not provide additional benefits and, thus, without proportional improvements for the additional effort, the enjoyment, motivation, or enthusiasm for exercise may diminish [69]. Although there is some disagreement [59], if optimal or more substantial muscle strength, endurance, and hypertrophy gains are the goal, then multiple weekly training sessions are recommended over single weekly sessions, especially for the more highly trained or active individuals [19,25,26,30,49,[51][52][53][54][55][56]. However, the evidence does indicate that a RT program beginning with a single session per week can provide strength gains for sedentary or less active individuals who are only interested in the minimal weekly RT frequency to attain significant muscle strength and endurance gains over at least 8-12 weeks. ...
Background Findings from original research, systematic reviews, and meta-analyses have demonstrated the effectiveness of resistance training (RT) on markers of performance and health. However, the literature is inconsistent with regards to the dosage effects (frequency, intensity, time, type) of RT to maximize training-induced improvements. This is most likely due to moderating factors such as age, sex, and training status. Moreover, individuals with limited time to exercise or who lack motivation to perform RT are interested in the least amount of RT to improve physical fitness. Objectives The objective of this review was to investigate and identify lower than typically recommended RT dosages (i.e., shorter durations, lower volumes, and intensity activities) that can improve fitness components such as muscle strength and endurance for sedentary individuals or beginners not meeting the minimal recommendation of exercise. Methods Due to the broad research question involving different RT types, cohorts, and outcome measures (i.e., high het-erogeneity), a narrative review was selected instead of a systematic meta-analysis approach. Results It seems that one weekly RT session is sufficient to induce strength gains in RT beginners with < 3 sets and loads below 50% of one-repetition maximum (1RM). With regards to the number of repetitions, the literature is controversial and some authors report that repetition to failure is key to achieve optimal adaptations, while other authors report similar adaptations with fewer repetitions. Additionally, higher intensity or heavier loads tend to provide superior results. With regards to the RT type, multi-joint exercises induce similar or even larger effects than single-joint exercises. Conclusion The least amount of RT that can be performed to improve physical fitness for beginners for at least the first 12 weeks is one weekly session at intensities below 50% 1RM, with < 3 sets per multi-joint exercise.
... This recommendation is in accord with other reviews and association recommendations, which provide typical minimum recommendation for RT weekly frequency of two to three times per week in order to achieve significant increases in muscle strength, endurance, and hypertrophy [19,25,26,30,49,51,52]. Multiple weekly RT sessions are often reported to provide greater positive strength and endurance adaptations than fewer sessions; 4 > 2 [53], 3 > 1 [54], 5 > 1 [55,56], which would suggest that greater RT volumes may be more effective. However, the literature is not unanimous. ...
... Hence, for the previously sedentary individual, multiple RT sessions per week may not provide additional benefits and, thus, without proportional improvements for the additional effort, the enjoyment, motivation, or enthusiasm for exercise may diminish [69]. Although there is some disagreement [59], if optimal or more substantial muscle strength, endurance, and hypertrophy gains are the goal, then multiple weekly training sessions are recommended over single weekly sessions, especially for the more highly trained or active individuals [19,25,26,30,49,[51][52][53][54][55][56]. However, the evidence does indicate that a RT program beginning with a single session per week can provide strength gains for sedentary or less active individuals who are only interested in the minimal weekly RT frequency to attain significant muscle strength and endurance gains over at least 8-12 weeks. ...
Background
Findings from original research, systematic reviews, and meta-analyses have demonstrated the effectiveness of resistance training (RT) on markers of performance and health. However, the literature is inconsistent with regards to the dosage effects (frequency, intensity, time, type) of RT to maximize training-induced improvements. This is most likely due to moderating factors such as age, sex, and training status. Moreover, individuals with limited time to exercise or who lack motivation to perform RT are interested in the least amount of RT to improve physical fitness.
Objectives
The objective of this review was to investigate and identify lower than typically recommended RT dosages (i.e., shorter durations, lower volumes, and intensity activities) that can improve fitness components such as muscle strength and endurance for sedentary individuals or beginners not meeting the minimal recommendation of exercise.
Methods
Due to the broad research question involving different RT types, cohorts, and outcome measures (i.e., high heterogeneity), a narrative review was selected instead of a systematic meta-analysis approach.
Results
It seems that one weekly RT session is sufficient to induce strength gains in RT beginners with < 3 sets and loads below 50% of one-repetition maximum (1RM). With regards to the number of repetitions, the literature is controversial and some authors report that repetition to failure is key to achieve optimal adaptations, while other authors report similar adaptations with fewer repetitions. Additionally, higher intensity or heavier loads tend to provide superior results. With regards to the RT type, multi-joint exercises induce similar or even larger effects than single-joint exercises.
Conclusion
The least amount of RT that can be performed to improve physical fitness for beginners for at least the first 12 weeks is one weekly session at intensities below 50% 1RM, with < 3 sets per multi-joint exercise.
... It is well established in the literature that RT programs carried out in different frequencies (e.g. 1-6 sessions·wk -1 ) induce positive effects on muscle strength and hypertrophy outcomes in resistance-trained subjects (11,23,36,42,45,52). Therefore, the present study expands on previous findings by providing direct evidence that performing 16 RT sessions in 8 weeks with a frequency of 2 sessions·wk -1 is as efficient as performing the same 16 sessions, but in 4 weeks with a frequency of 4 sessions·wk -1 to promote positive changes on morphofunctional responses. ...
International Journal of Exercise Science 15(4): 1661-1679, 2022. The purpose of the present study was to investigate muscle thickness and strength outcomes of the quadriceps femoris induced by different resistance training (RT) frequencies and detraining. In addition, muscle architecture (MA) parameters were also assessed. Twenty-seven healthy resistance-trained subjects (men, n = 17; women, n = 10; 20.8 ± 1.9 years; RT experience = 3.3 ± 1.6 years) volunteered to participate in this study. One leg of each subject was randomly allocated into the 2 sessions per week condition (2x) and the contralateral leg was then placed in the 4 sessions per week condition (4x). There were 16 RT sessions in 2x and 4x. After 4 weeks, 4x were divided into 2 other conditions: more 4 weeks with 2x(4x (+2x)) and detraining (4x (+Det)). Muscle thickness (MT), fascicle length (FL), pennation angle (PA) of the quadriceps muscles and one-repetition maximum for unilateral knee extension (1RMKE) were evaluated. A significant increase of 1RMKE in 2x, 4x, and 4x (+2x) and a decrease in 4x (+Det) was observed (all p < 0.05). The MA showed similar results in most dependent variables for MT, FL and PA. Specifically 4x (+Det) condition demonstrated antagonistic results when compared to the 4x (+2x) in MT of rectus femoris (p = 0.001) and increased FL in vastus intermedius (p = 0.001).
... This can be achieved by mediating different training variables based on the frequency, intensity, type, and time (FITT) principles [11]. Hereby a gradual increase in the number of repetitions or sets performed; a progressive increase in the weight lifted during exercises; an intensified exercise through reduced rest periods, advanced techniques, or more challenging variations; and/or an increased frequency of resistance training sessions generate further muscle growth and adaptation [12]. ...
Resistance training is an exercise modality that involves using weights or resistance to strengthen and tone muscles. It has become popular in recent years, with numerous people including it in their fitness routines to ameliorate their strength, muscle mass, and overall health. Still, resistance training can be complex, requiring careful planning and execution to avoid injury and achieve satisfactory results. Wearable technology has emerged as a promising tool for resistance training, as it allows monitoring and adjusting training programs in real time. Several wearable devices are currently available, such as smart watches, fitness trackers, and other sensors that can yield detailed physiological and biomechanical information. In resistance training research, this information can be used to assess the effectiveness of training programs and identify areas for improvement. Wearable technology has the potential to revolutionize resistance training research, providing new insights and opportunities for developing optimized training programs. This review examines the types of wearables commonly used in resistance training research, their applications in monitoring and optimizing training programs, and the potential limitations and challenges associated with their use. Finally, it discusses future research directions, including the development of advanced wearable technologies and the integration of artificial intelligence in resistance training research.
En la actualidad, los métodos de entrenamiento más recurrentes para el aumento de la potencia en las extremidades inferiores de los basquetbolistas, son el entrenamiento pliométrico y el entrenamiento con fuerza explosiva, pero no se ha determinado cual demuestra mayor eficiencia y efectividad en el mejoramiento de dicha capacidad Objetivo: comparar dos planes de entrenamiento, uno basado en pliometría y el otro en fuerza explosiva con basquetbolistas de 12 a 14 años. Metodología: proyecto cuantitativo, con línea de profundidad comparativa y diseño preexperimental. La población total fue de 50 individuos y la muestra se realizó a conveniencia, seleccionando 40 basquetbolistas, los cuales fueron distribuidos en dos grupos, 20 para el programa de fuerza explosiva (G1) y 20 para el programa pliométrico (G2). El instrumento utilizado para la recolección de datos fue la aplicación My Jump 2, Resultados: el programa de entrenamiento pliométrico muestra mejores resultados con una SD en SJ de 5.2 y en CMJ con 5.7 frente al programa de fuerza explosiva, donde presenta una SD en SJ de 6.1 y en CMJ con 6.3 Discusión: la mejora en los dos grupos presentó una significancia de (p<0,05) en comparación con otros modelos de trabajo como el de (Agudo y Castañeda, 2017) donde presentan el mismo nivel de significancia y afirman que el entrenamiento pliométrico demuestra resultados eficientes en jóvenes basquetbolistas . Conclusiones: el programa de entrenamiento pliométrico demuestra mejores resultados que el programa de fuerza explosiva.
Background: Weekly set volume and frequency are used to manipulate resistance training (RT) dosage. Previous research has identified higher weekly set volume as enhancing muscle hypertrophy and strength gains, but the nature of the dose-response relationship still needs to be investigated. Mixed evidence exists regarding the effects of higher weekly frequency. Objective: Before meta-analyzing the volume and frequency research, all contributing RT sets were classified as direct or indirect, depending on their specificity to the hypertrophy/strength measurement. Then, weekly set volume/frequency for indirect sets was quantified as 1 for 'total,' 0.5 for 'fractional,' and 0 for 'direct.' A series of multi-level meta-regressions were performed for muscle hypertrophy and strength, utilizing 67 total studies of 2,058 participants. All models were adjusted for the duration of the intervention and training status. Results: The relative evidence for the 'fractional' quantification method was strongest; therefore, this quantification method was used for the primary meta-regression models. The posterior probability of the marginal slope exceeding zero for the effect of volume on both hypertrophy and strength was 100%, indicating that gains in muscle size and strength increase as volume increases. However, both best fit models suggest diminishing returns, with the diminishing returns for strength being considerably more pronounced. The posterior probability of the marginal slope exceeding zero for frequency's effect on hypertrophy was less than 100%, indicating compatibility with negligible effects. In contrast, the posterior probability for strength was 100%, suggesting strength gains increase with increasing frequency, albeit with diminishing returns. Conclusions: Distinguishing between direct and indirect sets appears essential for predicting adaptations to a given RT protocol, such as using the 'fractional' quantification method. This method's dose-response models revealed that volume and frequency have unique dose-response relationships with each hypertrophy and strength gain. The dose-response relationship between volume and hypertrophy appears to differ from that with strength, with the latter exhibiting more pronounced diminishing returns. The dose-response relationship between frequency and hypertrophy appears to differ from that with strength, as only the latter exhibits consistently identifiable effects.
The phytoecdysteroid 20-hydroxyecdysone (20E) is widely used for resistance training (RT). Little is known about its potential ergogenic value and detraining effects post-RT. This study aimed to examine the effects of 20E extracted from Asparagus officinalis (A. officinalis) on muscle strength and mass, as well as anabolic and catabolic hormones following RT and detraining. Twenty males, aged 20.1 ± 1.1 years, were matched and randomly assigned to consume double-blind supplements containing either a placebo (PLA) or 30 mg/day of 20E for 12 weeks of RT and detraining. Before and after RT and detraining, muscle strength and mass and anabolic and catabolic hormones were measured. This study found that 20E reduced cortisol levels significantly (p < 0.05) compared to the PLA, yet no effect was observed on muscle mass, strength, or anabolic hormones after RT. Subsequent to 6 weeks of detraining, the 20E demonstrated a lower percentage change in 1RM bench press/FFM than the PLA (p < 0.05). Compared to the PLA, detraining throughout the 12 weeks resulted in a lower percentage change in thigh (p < 0.05) and chest (p < 0.01) circumferences, as well as reduced cortisol levels (p < 0.01), with 20E. Our findings demonstrate that 20E supplementation is a promising way to maintain muscle mass and strength during detraining. Accordingly, 20E may prevent muscle mass and strength loss due to detraining by lowering catabolic hormone levels.
To compare the physiological and performance adaptations between periodized and nonperiodized resistance training in women collegiate tennis athletes.
Thirty women (19 +/- 1 yr) were assigned to either a periodized resistance training group (P), nonperiodized training group (NV), or a control group (C). Assessments for body composition, anaerobic power, VO2(max), speed, agility, maximal strength, jump height, tennis-service velocity, and resting serum hormonal concentrations were performed before and after 4, 6, and 9 months of resistance training performed 2-3 d.wk (-1).
Nine months of resistance training resulted in significant increases in fat-free mass; anaerobic power; grip strength; jump height; one-repetition maximum (1-RM) leg press, bench press, and shoulder press; serve, forehand, and backhand ball velocities; and resting serum insulin-like growth factor-1, testosterone, and cortisol concentrations. Percent body fat and VO2(max) decreased significantly in the P and NV groups after training. During the first 6 months, periodized resistance training elicited significantly greater increases in 1-RM leg press (9 +/- 2 vs 4.5 +/- 2%), bench press (22 +/- 5 vs 11 +/- 8%), and shoulder press (24 +/- 7 vs 18 +/- 6%) than the NV group. The absolute 1-RM leg press and shoulder press values in the P group were greater than the NV group after 9 months. Periodized resistance training also resulted in significantly greater improvements in jump height (50 +/- 9 vs 37 +/- 7%) and serve (29 +/- 5 vs 16 +/- 4%), forehand (22 +/- 3 vs 17 +/- 3%), and backhand ball velocities (36 +/- 4 vs 14 +/- 4%) as compared with nonperiodized training after 9 months.
These data demonstrated that periodization of resistance training over 9 months was superior for enhancing strength and motor performance in collegiate women tennis players.
Regimented resistance training has been shown to promote marked increases in skeletal muscle mass. Although muscle hypertrophy can be attained through a wide range of resistance training programs, the principle of specificity, which states that adaptations are specific to the nature of the applied stimulus, dictates that some programs will promote greater hypertrophy than others. Research is lacking, however, as to the best combination of variables required to maximize hypertophic gains. The purpose of this study was to investigate muscular adaptations to a volume-equated bodybuilding-type training program versus a powerlifting-type routine in well-trained subjects. 17 young men were randomly assigned to either an HT group that performed 3 sets of 10RM with 90 seconds rest or an ST group that performed 7 sets of 3RM with 3 minutes rest. After 8 weeks, no significant differences were noted in muscle thickness of the biceps brachii. Significant strength differences were found in favor of ST for the 1RM bench press and a trend was found for greater increases in the 1RM squat. In conclusion, this study showed both bodybuilding- and powerlifting-type training promote similar increases in muscular size, but powerlifting-type training is superior for enhancing maximal strength.
The purpose of this study was to investigate the time course of hypertrophic adaptations in both the upper arm and trunk muscles following high-intensity bench press training. Seven previously untrained young men (aged 25 ± 3 years) performed free-weight bench press training 3 days (Monday, Wednesday and Friday) per week for 24 weeks. Training intensity and volume were set at 75% of one repetition maximum (1-RM) and 30 repetitions (3 sets of 10 repetitions, with 2-3 min of rest between sets), respectively. Muscle thickness (MTH) was measured using B-mode ultrasound at three sites: the biceps and triceps brachii and the pectoralis major. Measurements were taken a week prior to the start of training, before the training session on every Monday and 3 days after the final training session. Pairwise comparisons from baseline revealed that pectoralis major MTH significantly increased after week-1 (p = 0.002), triceps MTH increased after week-5 (p = 0.001) and 1-RM strength increased after week-3 (p = 0.001) while no changes were observed in the biceps MTH from baseline. Significant muscle hypertrophy was observed earlier in the chest compared to that of the triceps. Our results indicate that the time course of the muscle hypertrophic response differs between the upper arm and chest.
Nutrient timing is a popular nutritional strategy involves the consumption of combinations of nutrients--primarily protein and carbohydrate--in and around an exercise session. Some have claimed that this approach can produce dramatic improvements in body composition. It has even been postulated that the timing of nutritional consumption may be more important than the absolute daily intake of nutrients. The post-exercise period is widely considered the most critical part of nutrient timing. Theoretically, consuming the proper ratio of nutrients during this time not only initiates the rebuilding of damaged muscle tissue and restoration of energy reserves, but it does so in a supercompensated fashion that enhances both body composition and exercise performance. Several researchers have made reference to an anabolic "window of opportunity" whereby a limited time exists after training to optimize training-related muscular adaptations. However, the importance - and even the existence - of a post-exercise 'window' can vary according to a number of factors. Not only is nutrient timing research open to question in terms of applicability, but recent evidence has directly challenged the classical view of the relevance of post-exercise nutritional intake with respect to anabolism. Therefore, the purpose of this paper will be twofold: 1) to review the existing literature on the effects of nutrient timing with respect to post-exercise muscular adaptations, and; 2) to draw relevant conclusions that allow practical, evidence-based nutritional recommendations to be made for maximizing the anabolic response to exercise.
Previous studies have reported for the vastus lateralis (VL) that the extent of muscle hypertrophy in response to resistance training is greater in the distal than in the middle region, despite uniform muscle fibre composition within VL along its length. In the present study, to investigate mechanism(s) for such non-uniform muscle hypertrophy, we simultaneously measured neuromuscular activity and muscle oxygenation state at the middle and distal regions of VL during fatiguing heavy resistance exercise. Twelve males performed unilateral knee extension exercise which consisted of 4 sets of 8 repetitions at intensity of 80% of the individual one repetition maximum. During the resistance exercise, neuromuscular activities and muscle oxygenation status at the middle and distal regions (50% and 70% of the thigh length, respectively) of VL were measured by using electromyography and near-infrared spectroscopy, respectively. Neuromuscular activities were similar between the distal and middle regions of VL, whereas muscle tissue oxygenation saturation was significantly lower at the distal than at the middle region of VL. These results suggest a possibility that the regional difference in muscle oxygenation but not in neuromuscular activity during fatiguing heavy resistance exercise is responsible for the regional difference in hypertrophy within a muscle.
Purpose:
Muscle hypertrophy in response to resistance training has been reported to occur nonuniformly along the length of the muscle. The purpose of the present study was to examine whether the regional difference in muscle hypertrophy induced by a training intervention corresponds to the regional difference in muscle activation in the training session.
Methods:
Twelve young men participated in a training intervention program for the elbow extensors with a multijoint resistance exercise for 12 wk (3 d · wk(-1)). Before and after the intervention, cross-sectional areas of the triceps brachii along its length were measured with magnetic resonance images. A series of transverse relaxation time (T2)-weighted magnetic resonance images was recorded before and immediately after the first session of training intervention. The T2 was calculated for each pixel within the triceps brachii. In the images recorded after the session, the number of pixels with a T2 greater than the threshold (mean + 1 SD of T2 before the session) was expressed as the ratio to the whole number of pixels within the muscle and used as an index of muscle activation (percent activated area).
Results:
The percent activated area of the triceps brachii in the first session was significantly higher in the middle regions than that in the most proximal region. Similarly, the relative change in cross-sectional area induced by the training intervention was also significantly greater in the middle regions than the most proximal region.
Conclusion:
The results suggest that nonuniform muscle hypertrophy after training intervention is due to the region-specific muscle activation during the training session.
There is not a strong research basis for current views of the importance of individual training variables in strength training protocol design. This study compared 1 day versus 3 days of resistance training per week in recreational weight trainers with the training volume held constant between the treatments. Subjects were randomly assigned to 1 of 2 groups: 1 day per week of 3 sets to failure (1DAY) or 3 days per week of 1 set to failure (3DAY). Relative intensity (percent of initial 1 repetition maximum [1RM]) was varied throughout the study in both groups by using a periodized repetition range of 3-10. Volume (repetitions x mass) did not differ (p <= 0.05) between the groups over the 12 weeks. The 1RMs of various upper-and lower-body exercises were assessed at baseline and at weeks 6 and 12. The 1RMs increased (p <= 0.05) significantly for the combined groups over time. The 1DAY group achieved ~62% of the 1RM increases observed in the 3DAY group in both upper-body and lower-body lifts. Larger increases in lean body mass were apparent in the 3DAY group. The findings suggest that a higher frequency of resistance training, even when volume is held constant, produces superior gains in 1RM. However, training only 1 day per week was an effective means of increasing strength, even in experienced recreational weight trainers. From a dose-response perspective, with the total volume of exercise held constant, spreading the training frequency to 3 doses per week produced superior results.
(C) 2000 National Strength and Conditioning Association
This study aimed to investigate the accuracy of estimating the volume of limb muscles (MV) using ultrasonographic muscle thickness (MT) measurements. The MT and MV of each of elbow flexors and extensors, knee extensors and ankle plantar flexors were determined from a single ultrasonographic image and multiple magnetic resonance imaging (MRI) scans, respectively, in 27 healthy men (23–40 years of age) who were allocated to validation (n=14) and cross-validation groups (n=13). In the validation group, simple and multiple regression equations using MT and a set of MT and limb length, respectively, as independent variables were derived to estimate the MV measured by MRI. However, only the multiple regression equations were cross-validated, and so the prediction equations with r
2 of 0.787–0.884 and the standard error of estimate of 22.1 cm3 (7.3%) for the elbow flexors to 198.5 cm3 (11.1%) for the knee extensors were developed using the pooled data. This approach did not induce significant systematic error in any muscle group, with no significant difference in the accuracy of estimating MV between muscle groups. In the multiple regression equations, the relative contribution of MT for predicting MV varied from 41.9% for the knee extensors to 70.4% for the elbow flexors. Thus, ultrasonographic MT measurement was a good predictor of MV when combined with limb length. For predicting MV, however, the unsuitability of a simple equation using MT only and the difference between muscle groups in the relative contribution of MT in multiple regression equations indicated a need for further research on the limb site selected and muscle analyzed for MT measurement.