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The Effects of Different Intensities and Durations of the General Warm-up on Leg Press 1RM
Abstract
The precision of maximum strength assessments (1RM) is important to evaluate the functional capacity and to prescribe and to monitor the training load. Several factors can affect the precision of 1RM tests, including the warm-up procedure. General and specific warm-up routines are recommended in order to enhance performance. The effects of a specific warm-up have already been acknowledged in improving performance. However, the effects of a general warm-up are unclear but seem to depend on its ability to increase muscle temperature while avoiding fatigue. Further, temperature elevation is dependent on both the duration and the intensity of the activity, which may eventually affect 1RM performance. The objective of this study was to investigate the effect of different intensities and durations of general warm-up on 1RM performance. Sixteen strength-trained males were tested for 1RM leg-press after four general warm-up conditions following specific warm-up: short-duration low-intensity (i.e. 5 minutes at 40% VO2max) (SDLI), long-duration low-intensity (i.e. 15 minutes at 40% VO2max) (LDLI), short-duration moderate-intensity (i.e. 5 minutes at 70% VO2max) (SDMI), long-duration moderate-intensity (i.e. 15 minutes at 70% VO2max) (LDMI), and the control (CTRL) no-general warm-up condition. Leg press 1RM values were higher (on average 3%) when subjects performed LDLI (367.8 ± 70.1 kg; p=0.01), compared to the other four conditions. Following the LDMI condition, 1RM values were lower (on average -4%) than in the other four conditions (345.6 ± 70.5 kg; p=0.01). There were no differences between SDMI, SDLI, and CTRL (359.4 ± 69.2 kg, 359.1 ± 69.3 kg, and 359.4 ± 70.4 kg, respectively) (p=0.99). According to our results long-duration low-intensity general warm up seems be appropriately to improve 1RM performance in strength-trained individuals.
... We attempt to explain this result using 2 approaches. First, body temperature is also one of the factors affecting maximal strength (3,5,19). This study found that performing CSE RW does not affect core temperature. ...
... However, performing CSE on USTA did not improve subsequent power and COD performance in the second half of the game. Previous studies have reported that performing RW or warm-up brings both benefits and fatigue (3,5,19,38). When the intensity of the warm-up activity is increased, higher benefits may occur but are also accompanied by higher levels of fatigue (3,5,19,38). ...
... Previous studies have reported that performing RW or warm-up brings both benefits and fatigue (3,5,19,38). When the intensity of the warm-up activity is increased, higher benefits may occur but are also accompanied by higher levels of fatigue (3,5,19,38). Previous research has pointed out that under the same warm-up duration, compared with performing a warm-up with 40% VȮ 2 max, the warm-up activity with 70% VȮ 2 max seems to induce a higher level of fatigue, which hinders subsequent exercise performance (3). ...
Yang, Y-R, Chen, C, Pan, C-H, Yen, S-Y, and Cheng, C-F. Effects of half-time re-warm-up with core strength exercises on subsequent agility and power performance in basketball players. J Strength Cond Res XX(X): 000-000, 2024-This study investigated the effects of half-time re-warm-up (RW) comprising core strength exercise (CSE) on basketball players' subsequent power and change of direction (COD) performance. Twelve male collegiate basketball players were recruited to perform 3 conditions -CSE RW on a stable platform (STA) or an unstable platform (USTA) and passive rest (control, CON)-in randomized, counterbalanced order after a modified Loughborough intermittent shuttle test (LIST). The COD and power performance tests were administered before the LIST and after the interventions. Heart rate (HR) was continuously measured during each trial. Results showed significantly lower changes in T-test time in STA compared with CON (p , 0.05). Changes in countermovement jump height in STA were significantly higher than those in CON (p , 0.05). During the isometric midthigh pull test, changes in the maximum rate of force development (RFD) (p , 0.05), RFD in the range of 0-90 milliseconds (p , 0.05), 0-150 milliseconds (p , 0.05), 0-200 milliseconds (p , 0.05), and 0-250 milliseconds (p , 0.05), in STA were significantly higher than those in CON. In addition, RFD in the range of 0-150 milliseconds (p , 0.05) and 0-250 milliseconds (p , 0.05) in USTA was significantly higher than that in CON. The mean HR during USTA was significantly higher than that in STA and CON (p , 0.05). These findings indicated that CSE RW during halftime might prevent power and COD performance decline in the second half of a game, with practical implications for coaches and players.
... This consisted of a 15-minute stationary cycle (40% VO2 max), followed by 3 sets of 10 reps bodyweight squats and 2 sets of 8 reps of isometric hamstring curls (90° hip, 90° knee; 50% 1RM load), holding the contraction in mid-range for 5 seconds using the KT360 pads to meet the participants resistance. 16 The participants knee flexion was then tested in both the right and left limbs. This was measured in supine with arms across the chest, aligned pelvis, and neutral knee position, with knees over toes. ...
Background
Fixed-frame dynamometry systems are used worldwide to assess isometric strength in both general and athletic populations. There is currently a paucity of published work where reliability estimates for fixed-frame dynamometry systems have been estimated. The aim of this study was to determine the inter-and intra-rater reliability of the KangaTech (KT360) fixed frame dynamometry system when measuring maximal isometric strength of the knee flexor muscles.
Study Design
Inter and intra-rater reliability single cohort study.
Methods
Twenty healthy university-level athletes (age= 21.65 ± 3 years, weight= 74.465 ± 30kg, height= 170.1 ± 7.0cm) took part in two testing sessions where two raters collected data during a 90° hip and knee flexion protocol. Participants performed each test twice, building to a maximal isometric contraction holding over a 5 second period with 30 second rest between sets. Data were checked for normality using a Shapiro-Wilk test. Intraclass correlation coefficient (ICC), standard error of measurement (SEM) and minimal detectable change (MDC) were calculated. Finally, a Bland-Altman analysis was used to determine the levels of agreement for intra-and inter-rater measurements.
Results
High levels of agreement were demonstrated between left and right knee flexion as 95% of the differences were less than two standard deviations away from the mean. ‘Almost perfect’ intraclass correlation coefficient (ICC) values were demonstrated (Knee flexion: Inter-rater: Left, 0.99; Right, 0.99; Intra-rater: Left, 0.99; Right:0.99). Standard error of measurement (SEM) for inter-and intra-rater strength ranged from 0.26-0.69 kg, SEM% ranged from 1.34-2.71% and minimal detectable change (MDC) ranged from 1.14-2.31kg.
Conclusion
Overall, high level of inter-and intra-rater reliability were demonstrated when testing maximal isometric knee flexion. Therefore, the KT360 fixed frame dynamometry system may be considered a viable tool for measuring maximal isometric contraction of the knee flexors when repeat measures are required in clinical settings.
Level of Evidence
3b
... Las investigaciones actuales son contradictorias sobre si el estímulo vibratorio de todo el cuerpo tiene o no un efecto significativo sobre la altura, la potencia, el equilibrio y la agilidad del salto vertical (Wallman et al., 2019). Estudios previos demostraron que la vibración de cuerpo completo aumentaba la temperatura intramuscular (Cochrane et al., 2008) y no solo inducía un beneficio de PAP, sino que también mejoraba la resistencia a la fatiga (Barroso et al., 2013). ...
El uso de la realidad virtual y plataformas inestables en el ámbito deportivo ha ganado interés en el último tiempo por su potencial para mejorar el rendimiento físico gracias a la simulación de distintos entornos. En este sentido, es necesario investigar los efectos del ejercicio de alta intensidad utilizando realidad virtual en una plataforma inestable sobre la fuerza de las extremidades inferiores, por lo cual, el objetivo planteado fue identificar el efecto agudo de una sesión de realidad virtual con una plataforma inestable para repetir saltos en estudiantes universitarios. Para la investigación se incluyó una muestra de 268 estudiantes universitarios divididos en tres grupos. Se evaluó la fuerza de las extremidades inferiores a través de saltos, tanto PRE y POST ejercicio. Se observaron diferencias en la altura del Squat Jump (SJ) dentro de tres grupos (F=39.32; p<0.001; d=0.217). En el counter movement jump (CMJ) también se observaron diferencias (F=11.67; p<0.001; d=0.076). No hubo diferencias en la altura de salto abalakov (ABALA) entre los grupos (F=8.73; p<0.001; d=0.058). Sin embargo, no se registraron diferencias entre los grupos antes y posterior a la intervención (p<0.05). El ejercicio de alta intensidad en realidad virtual en una plataforma inestable mejoró la fuerza y la capacidad de salto en estudiantes universitarios, en comparación con un ejercicio similar en una superficie estable. Sin embargo, el grupo ICAROS no mostró mejoras significativas en la altura de los saltos, aunque sí redujo el tiempo de duración entre ciertos saltos en la plataforma inestable. Estos resultados se relacionan con el fenómeno de potenciación postactivación (PAP) después del ejercicio intenso. En conclusión, este estudio sugiere que el ejercicio de alta intensidad usando realidad virtual en una plataforma inestable puede mejorar la fuerza de los miembros inferiores en estudiantes universitarios. Estos hallazgos subrayan el potencial de la realidad virtual como una herramienta innovadora en el entrenamiento deportivo. Palabras clave: Realidad virtual, plataformas inestables, PAP, PAPE, Icaros Cloud 360 Abstract. The use of virtual reality and unstable platforms in sports has recently gained interest due to its potential to improve physical performance by simulating different environments. In this sense, it is necessary to investigate the effects of high-intensity training using virtual reality on an unstable platform on the strength of the lower extremities, therefore the objective was to determine the acute effect of a virtual reality session with an unstable platform on repetitive jumps in university students. The research involved a sample of 268 university students divided into three groups. Lower limb strength was assessed by jumping, both PRE and POST. Differences in squat jump (SJ) height were observed within the three groups (F=39.32; p<0.001; d=0.217). Differences were also observed in the counter movement jump (CMJ) (F=11.67; p<0.001; d=0.076). There were no differences in Abalakov's jump height (ABALA) between groups (F=8.73; p<0.001; d=0.058). However, there were no differences between groups before and after the intervention (p<0.05). High-intensity virtual reality exercise on an unstable platform improved strength and jumping ability in college students compared to similar exercise on a stable surface. However, the ICAROS group did not show significant improvements in jump height, although they did reduce the time between certain jumps on the unstable platform. These results are related to the phenomenon of post-activation potentiation (PAP) after intense exercise. In conclusion, this study suggests that high-intensity exercise using virtual reality on an unstable platform can improve lower limb strength in college students. These findings highlight the potential of virtual reality as an innovative tool in sports training. Keywords: Virtual reality, unstable platforms, PAP, PAPE, Icaros Cloud 360
... When planning a RT session, it is common to use preparation methods before the principal sets (12), although the form adopted for this activity is quite different. In this regard, some researchers have investigated the effects of different preparation protocols on physical performance measures, particularly acutely before resistance exercises, to ascertain performance-related responses (1,3,16,20,23). ...
Preparation methods are used to improve performance within the resistance training session, however there is still no consensus in the scientific literature on the best form of preparation for the older adults. We compared the effects of preparation by specific warm-up (SW) and static stretching (SS) and control condition (CC) on the total number of repetitions in four exercises: leg extension, triceps pushdown, seated leg curl, preacher curl. Fifty-seven older women (60 > years) performed the experimental protocols and the control condition in a cross-balanced and counterbalanced design. Following the preparation protocol, the exercises were performed in two sets until volitional concentric failure, with a two-minute interval between sets and 2–3 minutes between exercises. The main outcome was the total number of repetitions. SS improved performance in total number of repetitions when compared to the other experimental conditions in lower limb exercises, while the SW impaired when compared to the other experimental conditions in upper limb exercise. The short-term static stretching can be used to increase performance in the leg extension and seated leg curl, while the specific warm-up should not be used as a form of preparation for the exercises in the triceps pushdown and preacher curl.
... In the present study, the comparison of traditional warm-up protocols, short-term high-intensity warm-up protocols, and without warm-up measurements is statistically significant, which agrees with a research article published by Mancilla et al. (2023), who report that there are significant differences between high-intensity warm-up protocols (37). These results are similar to previous studies where an increase in only vertical jump height was observed after a general, traditional, specific, or short-term high-intensity warm-up protocol (36,(38)(39)(40). However not all research agrees, and discrepancies between our findings and earlier studies could be attributed to how fatigued participants were during the shortterm high-intensity and traditional warm-up protocols (20,41,42). ...
Background. Volleyball warm-up protocols can lead to improvements in vertical jump performance. Objectives. The purpose of this study was to compare the immediate effects of a short-term high-intensity warm-up protocol and a traditional warm-up protocol on vertical jump height in elite and sub-elite women volleyball players. Methods. Thirty healthy volleyball players (aged 26.53±3.72 years; elite group n=14; sub-elite group n=16) performed a short-term high-intensity warm-up protocol (27 min) and a traditional warm-up protocol (45 min) over three days at 48-hour intervals. After each protocol, the vertical jump height was evaluated using the VERT wearable jump device. The ANOVA test for repeated measurements revealed a significant difference, and a Bonferroni post-hoc test was used. Results. In all groups, vertical jump height was significantly changed and increased from the short-term high-intensity warm-up protocol compared to the traditional warm-up protocol (Diff=-3.103; 95% CI=-4.118 to-2.088; d=0.81; p<0.001; ηp2=0.762) and the without warm-up (Diff=-4.973; 95% CI=-6.153 to-3.793; d=1.36; p<0.001). In the elite group, vertical jump height was significantly changed and increased from the short-term high-intensity warm-up protocol compared to the traditional warm-up protocol (Diff=3.943; 95% CI=1.962 to 5.924; d=1.24; p<0.001; ηp2=0.818) and the without warm-up (Diff=-6.543; 95% CI=-8.609 to-4.476; d=2.13; p<0.001). Similarly, in the sub-elite group, vertical jump height was also significantly changed and increased from the short-term high-intensity warm-up protocol compared to the traditional warm-up protocol (Diff=1.231; 95% CI=-0.717 to-1.746; d=0.68; p<0.001; ηp2=0.856) and the without warm-up (Diff=-3.600; 95% CI=-4.375 to-2.825; d=1.04; p<0.001). Conclusion. In conclusion, the results revealed that, in practical terms, the short-term high-intensity warm-up protocol is the best protocol to immediately improve vertical jump performance in women volleyball players. Robust conclusions, however, need randomized controlled trials with sufficient statistical power.
... In the present study, the comparison of traditional warm-up protocols, short-term high-intensity warm-up protocols, and without warm-up measurements is statistically significant, which agrees with a research article published by Mancilla et al. (2023), who report that there are significant differences between high-intensity warm-up protocols (37). These results are similar to previous studies where an increase in only vertical jump height was observed after a general, traditional, specific, or short-term highintensity warm-up protocol (36,(38)(39)(40). However not all research agrees, and discrepancies between our findings and earlier studies could be attributed to how fatigued participants were during the short-term highintensity and traditional warm-up protocols (20,41,42). ...
Background. Volleyball warm-up protocols can lead to improvements in vertical jump performance. Objectives. The purpose of this study was to compare the immediate effects of a short-term high-intensity warm-up protocol and a traditional warm-up protocol on vertical jump height in elite and sub-elite women volleyball players. Methods. Thirty healthy volleyball players (aged 26.53±3.72 years; elite group n=14; sub-elite group n=16) performed short-term high-intensity warm-up protocol (27 min) and a traditional warm-up protocol (45 min) over three days at 48-hour intervals. After each protocol, the vertical jump height was evaluated using the VERT wearable jump device. The ANOVA test for repeated measurements revealed a significant difference, and a Bonferroni post-hoc test was used. Results. In all groups, vertical jump height was significantly changed and increased from the short-term high-intensity warm-up protocol compared to the traditional warm-up protocol (Diff=-3.103; 95% CI=-4.118 to-2.088; d=0.81; p<0.001; ηp2=0.762) and the without warm-up (Diff=-4.973; 95% CI=-6.153 to-3.793; d=1.36; p<0.001). In the elite group, vertical jump height was significantly changed and increased from the short-term high-intensity warm-up protocol compared to the traditional warm-up protocol (Diff=3.943; 95% CI=1.962 to 5.924; d=1.24; p<0.001; ηp2=0.818) and the without warm-up (Diff=-6.543; 95% CI=-8.609 to-4.476; d=2.13; p<0.001). Similarly, in the sub-elite group, vertical jump height was also significantly changed and increased from the short-term high intensity warm-up protocol compared to the traditional warm-up protocol (Diff=1.231; 95% CI=-.717 to-1.746; d=0.68; p<0.001; ηp2=0.856) and the without warm-up (Diff=-3.600; 95% CI=-4.375 to-2.825; d=1.04; p<0.001). Conclusion. In conclusion, the results revealed that, in practical terms, the short-term high-intensity warm-up protocol is the best protocol to immediately improve vertical jump performance in women volleyball players. Robust conclusions, however, need randomized controlled trials with sufficient statistical power.
... A few studies have reported that 15-20 minutes of cycling at 40-60% of maximum heart rate (HRMAX) improved one repetition maximum (1RM) leg press. 7,8 These results suggest that lower-body aerobic exercise as a GW (LGW) improves the quantity and quality of lower-body RT. ...
Objective: This study aimed to examine whether the addition of lower-body aerobic exercise as a warm-up (LGW) improves upper-body resistance training (RT) performance more than a specific warm-up (SW) alone and to investigate whether maximal muscular strength modulates the performance-enhancing effect of LGW. Design: Randomized crossover design. Methods: Fourteen male participants performed 3 sets of 80%1RM bench press under two warm-up conditions. In one con dition, the participants performed only a SW for the bench press exercise. In the other condition (LGW + SW), the participants performed cycling for 20 minutes and the SW for the bench press exercise. Results: There was no statistically significant difference in the total number of repetitions (REPTOTAL) and the mean propulsive velocity (MPV) of the barbell during the concentric phase between the SW and LGW + SW. Also, 1RM did not modu late the relationship between SW and LGW + SW for REPTOTAL and maximum MPV among all sets. Conclusion: This study suggests that the LGW in addition to the SW does not have large additional effects on performance during upper-body RT. In addition, maximal muscular strength does not modulate the performance-enhancing effect of the LGW on upper-body RT performed at 80%1RM.
Background
Breast cancer patients undergoing chemotherapy experience body composition changes impacting treatment outcomes. The role of resistance training in mitigating chemotherapy‐induced sarcopenia in breast cancer patients is not well defined.
Aims
This study aims to assess the efficacy of resistance training in preventing sarcopenia among breast cancer patients undergoing chemotherapy.
Methods
A systematic search was conducted across PubMed, EMBASE, Medline, the Cochrane Library, and CINAHL until May 5, 2023. Selected literature focused on the effects of resistance training on body fat, muscle mass, muscle strength, and physical performance in breast cancer patients undergoing chemotherapy. Cochrane Risk of Bias tool version 2.0 was employed for quality assessment, and data were analyzed using Comprehensive Meta‐Analysis version 2.0.
Results
Eleven randomized controlled trials (RCTs) showed that resistance training had a significant positive impact on reducing body fat (SMD = −0.250, 95% CI [−0.450, −0.050]), increasing lean body mass (SMD = 0.374, 95% CI [0.178, 0.571]), and enhancing handgrip strength at both the affected site (SMD = 0.326, 95% CI [0.108, 0.543]) and the nonaffected site (SMD = 0.276, 95% CI [0.059, 0.492]). Additionally, significant improvements were observed in leg press strength (SMD = 0.598, 95% CI [0.401, 0.796]) and overall physical performance (SMD = 0.671, 95% CI [0.419, 0.923]).
Linking Evidence to Action
Resistance training is a recommended intervention for reducing body fat, increasing muscle mass, muscle strength, and enhancing physical performance in breast cancer patients undergoing chemotherapy. Ideal low‐intensity resistance training programs span 8–24 weeks, with 20‐to‐90‐min sessions 2–4 times weekly. Regimens generally entail 8–12 repetitions at 40%–90% of one‐repetition maximum test, with free‐weight resistance training targeting major muscle groups yielding substantial benefits. Further research should explore outcomes across different chemotherapy phases and investigate long‐term resistance training effects for a comprehensive view.
Introduction
Various pathophysiological contexts can be accompanied by weakness, arthrogenic muscle inhibition, and even disability. In this scenario, peripheral nerve stimulation has been studied not only for pain management but also for the improvement of neuromuscular parameters. For this purpose, the use of Transcutaneous Electrical Nerve Stimulation (TENS) has typically been investigated, but recently, the use of ultrasound-guided percutaneous peripheral nerve stimulation (pPNS) has gained popularity. In this regard, electrical stimulation has a predisposition to activate Type II muscle fibers and has been shown to be capable of generating short-term potentiation by increasing calcium sensitivity. However, the evidence of pPNS applied in humans investigating such variables is rather limited.
Objectives
This pilot study aimed to assess the feasibility of the methodology and explore the potential of pPNS in enhancing hip extension performance in individuals suffering from knee pain, comparing it with TENS.
Methods
Twelve participants were divided into pPNS and TENS groups, undergoing pre- and post-intervention assessments of peak concentric power (W), strength (N), execution speed (m/s), and one-repetition maximum (1RM) (kg) estimation. For pPNS, two needles were positioned adjacent to the superior and inferior gluteal nerves under ultrasound guidance. For TENS, electrodes were positioned between the posterosuperior iliac spine and the ischial tuberosity, and halfway between the posterosuperior iliac spine and the greater trochanter. The interventions consisted of 10 stimulations of 10 s at a frequency of 10 Hz with a pulse width of 240 μs, with rest intervals of 10 s between stimulations.
Results
Peripheral nerve stimulation significantly improved concentric power at 30% (p = 0.03) and 50% (p = 0.03) of 1RM, surpassing TENS, which showed minimal changes. No significant strength differences were observed post-intervention in either group.
Conclusion
This work presents evidence where pPNS applied to the gluteal nerves results in an enhanced performance of hip extension at submaximal loads. However, this improvement does not seem to be reflected in short-term changes in the estimation of the 1RM by the force-velocity profile.
Measures of neuromuscular function are commonly obtained in the research disciplines of aging, disease physiology, and exercise science. The methods used to assess neuromuscular function range in sophistication. Here, we provide comprehensive overviews of strength testing, dynamometer assessments, the use of force plates, and evoked potentials. Our goal is to guide the reader on how neuromuscular function can be assessed according to their research needs.Key wordsStrength testingEvoked contractionsDynamometer
Despite limited scientific evidence supporting their effectiveness, warm-up routines prior to exercise are a well-accepted practice. The majority of the effects of warm up have been attributed to temperature-related mechanisms (e.g. decreased stiffness, increased nerve-conduction rate, altered force-velocity relationship, increased anaerobic energy provision and increased thermoregulatory strain), although non-temperature-related mechanisms have also been proposed (e.g. effects of acidaemia, elevation of baseline oxygen consumption (V̇O2) and increased postactivation potentiation). It has also been hypothesised that warm up may have a number of psychological effects (e.g. increased preparedness). Warm-up techniques can be broadly classified into two major categories: passive warm up or active warm up. Passive warm up involves raising muscle or core temperature by some external means, while active warm up utilises exercise. Passive heating allows one to obtain the increase in muscle or core temperature achieved by active warm up without depleting energy substrates. Passive warm up, although not practical for most athletes, also allows one to test the hypothesis that many of the performance changes associated with active warm up can be largely attributed to temperature-related mechanisms.
While warm up is considered to be essential for optimum performance, there is little scientific evidence supporting its effectiveness in many situations. As a result, warm-up procedures are usually based on the trial and error experience of the athlete or coach, rather than on scientific study. Summarising the findings of the many warm-up studies conducted over the years is difficult. Many of the earlier studies were poorly controlled, contained few study participants and often omitted statistical analyses. Furthermore, over the years, warm up protocols consisting of different types (e.g. active, passive, specific) and structures (e.g. varied intensity, duration and recovery) have been used. Finally, while many studies have investigated the physiological responses to warm up, relatively few studies have reported changes in performance following warm up. The first part of this review critically analyses reported changes in performance following various active warm-up protocols. While there is a scarcity of well-controlled studies with large subject numbers and appropriate statistical analyses, a number of conclusions can be drawn regarding the effects of active warm up on performance. Active warm up tends to result in slightly larger improvements in short-term performance (10 seconds, but 2). While active warm up has been reported to improve endurance performance, it may have a detrimental effect on endurance performance if it causes a significant increase in thermoregulatory strain. The addition of a brief, task-specific burst of activity has been reported to provide further ergogenic benefits for some tasks. By manipulating intensity, duration and recovery, many different warm-up protocols may be able to achieve similar physiological and performance changes. Finally, passive warm-up techniques may be important to supplement or maintain temperature increases produced by an active warm up, especially if there is an unavoidable delay between the warm up and the task and/or the weather is cold. Further research is required to investigate the role of warm up in different environmental conditions, especially for endurance events where a critical core temperature may limit performance.
Different stretching techni- ques have been used during warm-up routines. However, these routines may decrease force production. The purpose of this study was to compare the acute effect of a ballistic and a static stretching protocol on lower-limb maximal strength. Fourteen physically active women (169.3 6 8.2 cm; 64.9 6 5.9 kg; 23.1 6 3.6 years) performed three experimental sessions: a control session (estimation of 45° leg press one-repetition maximum [1RM]), a ballistic session (20 minutes of ballistic stretch and 45° leg press 1RM), and a static session (20 minutes of static stretch and 45° leg press 1RM). Maximal strength decreased after static stretching (213.2 6 36.1 to 184.6 6 28.9 kg), but it was unaffected by ballistic stretching (208.4 6 34.8 kg). In addition, static stretching exercises produce a greater acute improvement in flexibility compared with ballistic stretching exercises. Consequently, static stretching may not be recom- mended before athletic events or physical activities that require high levels of force. On the other hand, ballistic stretching could be more appropriate because it seems less likely to decrease maximal strength.
The content of this manuscript is intended to assist the reader in collecting valid and reliable data for quantifying muscular strength and power. Various drawbacks and pitfalls of specific tests, as well as recommendations for the practitioner are also provided. The content is divided into sections covering isometric, isotonic, field tests, and isokinetic modes of exercise. Inherent in these modes are both concentric and eccentric muscle actions as well as both open and closed kinetic chain activities. For Isometric testing, contractions should occur over a four to five seconds duration with a one second transition period at the start of the contraction. At least one minute of rest should be provided between contractions. For each muscle tested at each position, at least three contractions should be performed although more may be performed if deemed necessary by the tester. For isotonic testing, the 1-RM test should be performed. After the general warm-up, the subject should perform a specific warm-up set of 8 repetitions at approximately 50% of the estimated 1-RM followed by another set of 3 repetitions at 70% of the estimated 1-RM. Subsequent lifts are single repetitions of progressively heavier weights until failure. Repeat until the 1-RM is determined to the desired level of precision. The rest interval between sets should be not less than one and not more than five minutes. The optimal number of single repetitions ranges from three to five. Data and guidelines of the following field tests are also provided; vertical jump, bench press, Wingate anaerobic cycle test (WAT), and the Margaria stair-run test. For isokinetic testing, details are provided for testing peak torque, work, power, endurance, and estimation of fiber type percentages.
Muscle temperature has a profound effect on the neuromuscular system of young individuals, however, little is known about the effects of altered temperature on the muscles of older individuals. The purpose of this study was to investigate the effect of altered local temperature on maximal torque and electromyography signal characteristics in 15 young (21.5 +/- 2.2 years; mean +/- SD) and 12 older (73.6 +/- 3.2 years) women. Subjects completed maximal voluntary isometric knee extension and flexion, together with isokinetic knee extensions (30, 60, 90, 120 and 240 degrees/s) at three muscle temperatures: control (approximately 34 degrees C), cold (approximately 30 degrees C) and warm (approximately 38 degrees C). The torque was lower in the older compared to young subjects at all temperatures (range of difference for 240 degrees /s, 25-40%; P < 0.001). Warming had no effect on torque in either group, whereas cooling decreased the torque during the isokinetic contractions in the young group only (range of decrease 6-10%; P < 0.05). In both groups, muscle fibre conduction velocity was slower with cooling compared to the warm condition (-15% in the young and -17% in the older subjects; P < 0.05).Temperature, however, had no effect on the agonist-antagonist coactivation level or the rate of force development in either group. The results suggest that, in particular, cooling the muscles has a greater effect on motor performance in young than older adults, which may indicate reduced adaptation of the neuromuscular system of older adults to altered temperature.
The purpose of this series of investigations was to gain insight on resistance training in American football and address some of the myths. Many theories about resistance training have been proposed, yet there has been little if any research on some of these training philosophies. This series of studies represents an accumulation of data that helped to formulate a training approach. Rather than having a training philosophy, it might be more productive to have a training approach based on facts and critical monitoring of test variables representative of the physical development possible through strength and conditioning programs. It was demonstrated that football players are capable of multiple maximal efforts in resistance training and that the length of the rest period was a determining factor. In general, multiple sets and various periodized training programs were superior to single-set programs in the rate and magnitude of improvements in body composition, strength, local muscular endurance, and power. Such data indicate that for building programs in previously trained football players, multiple-set programs that provide variation are more appropriate.
(C) 1997 National Strength and Conditioning Association
The purpose of this research was to determine whether a loaded countermovement jump (LCMJ) could be enhanced if preceded by a set of half-squats with a 5-RM load. Ten subjects experienced with the squat exercise performed 2 sets of 5 LCMJ, 1 set of 5 squat reps with a 5-RM load, and 1 set of 5 LCMJ with 4 min rest between all sets. There was no significant difference between the first 2 sets of LCMJ, and the repeatability between these sets was high. However, the jump height for the set of LCMJ after the squat set was significantly greater (2.8%) than for the LCMJ set immediately preceding the squats. It was concluded that squats with a 5-RM load produce dramatic improvements in power performance. In addition, there was a significant correlation between performance enhancement from the squats and the 5-RM load. This suggests that stronger individuals may benefit more from resistance training exercises that utilize contrasting loads.
(C) 1998 National Strength and Conditioning Association
Methods are described for the determination of ATP, CP, Pi, glycogen, G-6-P, and lactate concentrations in muscle specimens (15 mg) obtained with a needle biopsy technique. Muscle biopsy specimens were obtained in two materials (n = 13; maximal oxygen uptake (max V˙o2) 61 ml × min−3 × kg−1 and n = 15; average max V˙o2 48 ml × min−1 × kg−1), at submaxi mal (55–95 per cent of max V˙o2). and at short time exhaustive work levels. A depletion of the ATP and CP stores in relation to the relative work load was observed while the muscle lactate concentration increased faster at higher work loads concomitant with a tendency to an increased glycolysis. The ATP and CP stores (the phosphagens) could maximally account for an alactacid anaerobic energy output equivalent to 1.2–1.3 liters of oxygen. The lactacid anaerobic energy output, however, seemed to start when the phosphagens were lowered to approximately 70% of the basic values which occurred during steady-state work at work loads in excess of 50% of maximal oxygen uptake.
Accurate assessment of muscular strength is critical for exercise prescription and functional evaluation. The warm-up protocol may affect the precision of the 1 repetition maximum (1RM) test. Testing guidelines recommend performing both general and specific warm-ups before strength tests. The general warm-up intends to raise muscle temperature, whereas the specific warm-up aims to increase neuromuscular activation. Although there is scientific evidence for performing the specific warm-up, the effects of general warm-up on strength tests are still unclear. The purpose of this study was to investigate whether the combination of a general with a specific warm-up (G + SWU) protocol would improve leg press 1RM values compared with a specific warm-up (SWU) protocol. Thirteen participants were tested for leg-press 1RM under 2 warm-up conditions. In the first condition, participants performed the SWU only, which was composed of 1 set of 8 repetitions at approximately 50% of the estimated 1RM followed by another set of 3 repetitions at 70% of the estimated 1RM. In the second condition (G + SWU), participants performed the 1RM test after a 20-minute general warm-up on a stationary bicycle at 60% of HRmax and the same specific warm-up as in the SWU. Values of 1RM in SWU and in G + SWU were compared by a paired t-test, and significance level was set at p ≤ 0.05. Strength values were on average 8.4% (p = 0.002) higher in the G + SWU compared with the SWU. These results suggest that the G + SWU induced temperature-dependent neuromuscular adjustments that increased muscle force production capacity. Therefore, these results support the recommendations of the testing guidelines to perform a moderate intensity general warm-up in addition to the specific warm-up before maximum strength assessments.