High-Intensity Conditioning Activity Causes Localized Postactivation Performance Enhancement and Nonlocalized Performance Reduction.

ABSTRACT: Kolinger D, Stastny P, Pisz A, Krzysztofik M, Wilk M, Tsoukos A, and Bogdanis GC. High-intensity conditioning activity causes localized postactivation performance enhancement and nonlocalized performance reduction. J Strength Cond Res 38(1): e1-e7, 2024-This study aimed to examine whether a conditioning activity (CA) performed by the legs (barbell back squat) may cause postactivation performance enhancement (PAPE) on muscle groups other than leg extensors in isokinetic (eccentric [ECC] and concentric [CON]) and dynamic movement. Twelve male basketball players (age: 21.3 ± 3.2, body mass: 89.6 ± 14.1 kg, height: 187.4 ± 4.6 cm, and 1 repetition maximum (1RM) barbell back squat: 113 ± 21 kg) with previous resistance-training experience of at least 2 years, performed 3 sets of 3-4 repetitions of back-squats with submaximal load (60, 90, and 90% 1RM) as CA. Before and after the CA, they performed pretest and post-test in the form of countermovement jumps (CMJs) (localized) or explosive push-ups (EPUs) (nonlocalized) along with isokinetic flexion and extension at the knee (localized) or at the elbow (nonlocalized). The localized and nonlocalized protocols were divided into 2 days in a randomized order. The back squat as CA significantly increased peak torque (PT) (p < 0.05) in all CON and ECC muscle actions and average power per repetition (APPR) (p < 0.05) (all muscle actions except ECC flexion) of the localized isokinetic tests with large (>0.8) and medium (0.4-0.79) effect sizes and significantly decreased (p < 0.01) the PT and APPR (p < 0.01) of the nonlocalized isokinetic test in the ECC flexion. The CMJ and EPU tests showed no significant differences (p > 0.05) between premeasures and postmeasures of take-off height. The effect of PAPE seems to be specific to the muscles most involved in the CA, and the CA inhibits PT of subsequent muscle ECC contractions in muscles not involved in the CA.

Effects of different ischemic pressures on bar velocity during the bench press exercise: A randomized crossover trial.

The main objective of this study was to evaluate the effects of different ischemic pressures applied during rest intervals on bar velocity during the bench press exercise. 10 resistance-trained males (age = 23.2 ± 2.7 years; body mass = 83.9 ± 9 kg; body height = 181 ± 5.2 cm; bench press 1 repetition maximum (1RM) = 125 ± 16.4 kg; training experience = 5.4 ± 3.4 years) participated in the study. During 4 experimental sessions, following a randomized crossover design, the subjects performed 5 sets of 3 repetitions of the bench press exercise with a load of 60% 1RM under conditions: with ischemia (50% or 80% of arterial occlusion pressure), with SHAM ischemia (20 mmHg) and without ischemia (control condition). For the ischemic conditions cuffs were applied before each set for 6.5 min and released 30 s before the start of the set as reperfusion (6.5 min ischemia + 0.5 min reperfusion). In the control condition, ischemia was not applied. The two-way repeated measures ANOVA showed no significant condition × set interaction for mean bar velocity (MV; p = 0.17) and peak bar velocity (PV; p = 0.66). There was also no main effect of condition for MV (p = 0.58) and PV (p = 0.61). The results indicate that ischemic or SHAM treatment (6.5 minutes ischemia or SHAM + 30 s reperfusion) does not affect mean and peak bar velocity during the bench press exercise regardless of the applied pressure.

The Effects of the "Sling Shot" Device on Bench Press Performance, Mechanical Properties of Muscle, and Movement Kinematics.

ABSTRACT: Wojdala, G and Krzysztofik, M. The effects of the "sling shot" device on bench press performance, mechanical properties of muscle, and movement kinematics. J Strength Cond Res 37(4): 780-786, 2023-This study aimed to evaluate the influence of the sling shot support device at various external loads and intensities of effort, taking into account acute changes in power performance, mechanical muscle properties, and bench press kinematics. For this purpose, 12 resistance-trained men (age: 27.1 ± 4.2 years, body mass: 90.3 ± 16.9 kg, bench press [BP] 1 repetition maximum [1RM]: 112.7 ± 23.1 kg) (resistance training experience: 6.9 ± 3.8 years) participated in the study. Each subject completed 2 experimental sessions that differed in the use of the sling shot (SS) or nonuse (CONT) of the SS and an appropriate external load. The 2 experimental sessions consisted of the 1RM test, 3 sets of 2 repetitions of BP with the load increased in each set (50-70-90% 1RM), and a fourth set of the BP efforts to muscle failure with a 70% 1RM load. Before and after each set, the changes in triceps brachii oscillation frequency and stiffness were assessed by means of myotonometry. Results indicated a significant main effect of the SS to increase peak power ( p < 0.0001, η 2 = 0.733). Furthermore, a significantly higher 1RM (129 ± 26 vs. 113 ± 23 kg, p < 0.001, effect size [ES]: 0.63), number of repetitions (15 ± 3 vs. 13 ± 2, p = 0.013, ES: 0.76), and time under tension (34 ± 10 vs. 29 ± 6 seconds, p = 0.017, ES: 0.59) were found during the set to failure for SS in comparison to the CONT condition. Moreover, there was a significant main effect of time to increase oscillation frequency ( p = 0.001; η 2 = 0.666) and stiffness ( p = 0.002; η 2 = 0.613) from pre- to postset measure. In addition, the main effect of the side ( p = 0.034; η 2 = 0.348) was reported to show higher stiffness on the dominant than on the nondominant side in the CONT condition. The results suggest that an independent 1RM measurement and a correspondingly higher workload are required to take full advantage of the SS device. Moreover, the SS can also be used successfully to increase training volume and the involvement of nondominant limbs during a bench press.

Sprint Resisted and Assisted Priming for Peak Performance.

ABSTRACT: Krzysztof, K, Aleksander, M, Adam, Z, and Krzysztofik, M. Sprint resisted and assisted priming for peak performance. J Strength Cond Res 37(12): 2354-2361, 2023-This study aimed to investigate resisted and assisted sprint, or a combination of both, as a conditioning activity (CA) on creatine kinase activity, biceps femoris stiffness, postactivation performance enhancement (PAPE), and priming in a sprint. Ten female sprinters (age: 20.1 ± 2.3 years, body mass: 56.4 ± 4.2 kg, body height: 171 ± 5 cm, training experience: 5.6 ± 2 years) participated. Before the warm-up, blood samples were drawn to determine creatine kinase at baseline. After the warm-up, biceps femoris stiffness was determined, and consequently, 50-m sprint time (with 0- to 20-m and 20- to50-m split time evaluation) was assessed 5 minutes before (pre-CA) and in the seventh minute after the completion of each CA (4 sets of 40 m either: 10% body mass resisted [RST]; 105% maximum velocity assisted [AST] sprint; or 2 sets of each sprint as the CA [COMB]), as well as after 48 hours of recovery. Furthermore, another blood sample was taken 48 hours later, before the warm-up, to assess changes in creatine kinase activity. A significantly higher 20-m sprint time at post-CA ( p = 0.006; ES = 0.4) and post-48 ( p = 0.011; ES = 0.59) compared with pre-CA in the RST condition was found, whereas a significantly lower sprint time was reported in post-48 compared with post-CA ( p = 0.019; ES = 0.44) in the COMB condition. However, a significantly lower 30-m flying sprint time at post-CA ( p < 0.001; ES = 0.28) and at post-48 ( p = 0.014; ES = 0.22) compared with pre-CA in the RST condition was revealed. Moreover, a significantly lower 30-m flying sprint time at post-48 compared with the pre-CA ( p = 0.007; ES = 0.7 and p = 0.003; ES = 0.77) and with the post-CA ( p = 0.019; ES = 0.61 and p = 0.009; ES = 0.68) in the AST condition and COMB was reported. Furthermore, a significantly lower 50-m sprint time at post-48 compared with pre-CA ( p = 0.015; ES = 0.51 and p = 0.011; ES = 0.64) and with post-CA ( p = 0.005; ES = 0.46 and p = 0.001; ES = 0.55) in the AST and COMB condition were found. The creatine kinase activity at post-48 during AST was significantly lower than during RST ( p = 0.028; ES = 0.73) and COMB ( p = 0.028; ES = 1.48). No significant changes were found for biceps femoris stiffness ( p = 0.085; η 2 = 0.199). The COMB and AST contributed to the improvement of the 50-m sprint time 48 hours after activation, which may be a good precompetition approach. However, during training sessions aiming to induce an acute PAPE effect and improve the 30-m flying sprint time, the best solution might be to use low-volume-resisted sprints.

Acute Effects of Isometric Conditioning Activity on the Viscoelastic Properties of Muscles and Sprint and Jumping Performance in Handball Players.

ABSTRACT: Krzysztofik, M, Spieszny, M, Trybulski, R, Wilk, M, Pisz, A, Kolinger, D, Filip-Stachnik, A, and Stastny, P. Acute effects of isometric conditioning activity on the viscoelastic properties of muscles and sprint and jumping performance in handball players. J Strength Cond Res 37(7): 1486-1494, 2023-The effects of conditioning activity (CA) on muscle stiffness are currently unknown, suggesting that maximum CA effort can increase or decrease the stiffness of involved muscle groups. Therefore, this study aimed to investigate the effect of maximal isometric half-squats on the viscoelastic properties of muscles and postactivation performance enhancement (PAPE) in sprints and jumps. Twelve handball players underwent a standard warm-up and baseline assessment of muscle stiffness and tone of vastus lateralis and gastrocnemius medialis muscle, followed by 20-m sprint with intermediate measures at 5 and 10 m and countermovement jump. The PAPE was assessed by repeating the tests (at 4th, 8th, and 12th minute post-CA) after a CA protocol consisting of 3 sets of 3-second maximal isometric half-squats (EXP) or a control condition (CTRL) without any CA. The vastus lateralis stiffness in the 4th and 12th minute and muscle tone in the 4th minute post-CA significantly decreased compared with baseline ( p = 0.041, ES = 0.57; p = 0.013, ES = 0.52; p = 0.004, ES = 0.81, respectively) in the EXP condition. The 20-m sprint time significantly decreased at all post-CA time points compared with the baseline for the EXP condition ( p < 0.033) and the after values in the CTRL condition ( p < 0.036). In comparison to baseline, the 10-m sprint time decreased in the eighth minute post-CA ( p = 0.021; ES = 0.82) in the EXP condition. Moreover, it was significantly lower at the 8th and 12th minute post-CA ( p = 0.038; ES = 0.71 and p = 0.005; ES = 1.26) compared with that time points in the CTRL condition. The maximal isometric half-squats effectively improved sprint performance and significantly decreased vastus lateralis tone and stiffness. These findings offer new insights into the assessment of viscoelastic properties for evaluating the fatigue or potentiation state, which requires further investigation.

Acute Effects of Varied Back Squat Activation Protocols on Muscle-Tendon Stiffness and Jumping Performance.

ABSTRACT: Krzysztofik, M, Wilk, M, Pisz, A, Kolinger, D, Tsoukos, A, Zajac, A, Stastny, P, and Bogdanis, GC. Acute effects of varied back squat activation protocols on muscle-tendon stiffness and jumping performance. J Strength Cond Res 37(7): 1419-1427, 2023-Intensity, movement velocity, and volume are the principal factors to successfully use postactivation performance enhancement. Therefore, 15 resistance-trained volleyball players completed 3 different back squat configurations as a conditioning activity (CA) in randomized order: (a) 3 sets of 3 repetitions at 85% 1RM (HL); (b) a single set of back squats at 60% 1RM until 10% mean velocity loss (VB); (c) and 2 sets of back squats at 60% 1RM until 10% mean velocity loss (2VB) on subsequent countermovement jump performance, Achilles tendon, and vastus lateralis stiffness with concomitant front thigh skin surface temperature assessment. The measurements were performed 5 minutes before the CA and at 2, 4, 6, 8, and 10 minutes. The jump height was significantly increased in the second minute and at peak, post-CA compared with baseline for all conditions ( p = 0.049; ES = 0.23 and p < 0.001; ES = 0.37). Skin surface temperature was significantly increased for all post-CA time points compared with baseline in the 2VB condition ( p from <0.001-0.023; ES = 0.39-1.04) and in the fourth minute and at peak post-CA in HL condition ( p = 0.023; ES = 0.69 and p = 0.04; ES = 0.46), whereas for the VB condition, a significant decrease in peak post-CA was found ( p = 0.004; ES = -0.54). Achilles tendon stiffness was significantly decreased for second, fourth, eighth, 10th, and peak post-CA in comparison to baseline for all conditions ( p from p = 0.004-0.038; ES = -0.47 to -0.69). Vastus lateralis stiffness was significantly decreased for peak post-CA compared with baseline for all conditions ( p = 0.017; ES = -0.42). We recommend using a single set of barbell squats with a 10% velocity loss as a mechanism of fatigue control to acutely improve jump height performance and avoid unnecessary increases in training volume.

Acute Effects of High-Load vs. Plyometric Conditioning Activity on Jumping Performance and the Muscle-Tendon Mechanical Properties.

ABSTRACT: Krzysztofik, M, Wilk, M, Pisz, A, Kolinger, D, Bichowska, M, Zajac, A, and Stastny, P. Acute effects of high-load versus plyometric conditioning activity on jumping performance and the muscle-tendon mechanical properties. J Strength Cond Res 37(7): 1397-1403, 2023-The effectiveness of high-load and plyometric exercises as conditioning activity (CA) is not well described in the level of performance enhancement and muscle-tendon properties. Therefore, this study aimed to compare the effectiveness of high-loaded back squats and body mass tuck jumps among amateur soccer players on the height of countermovement jump performed without (CMJ) and with arm swing (CMJa) and to verify the usefulness of the myotonometry in assessing the level of CA-induced fatigue. Therefore, 16 male amateur soccer players (resistance training experience: 2 ± 1 year, relative 1 repetition maximum back squat strength: 1.41 ± 0.12 kg·body mass-1) performed 3 experimental sessions to compare the acute effects of 3 sets of 3 repetitions at 85% one repetition maximum of half back squats (HL), 3 sets of 5 repetitions of tuck jump exercises (PLY), and no CA (CTRL) on CMJ and CMJa height. Moreover, the gastrocnemius medialis and Achilles tendon tone and stiffness were examined. Measurements were performed 5 minutes before CA and in the third, sixth, and ninth minutes after CA. The CMJ height significantly increased from pre-CA to post-CA in the CTRL (p = 0.005; effect size [ES] = 0.36; Δ = +3.4%) and PLY (p = 0.001; ES = 0.83; Δ = +8.8%) conditions. Moreover, post-CA jump height was significantly higher in PLY than in the HL condition (p = 0.024; ES = 0.6; Δ = +5.9%). No significant differences were found for CMJa height, tone, and stiffness of gastrocnemius medialis and Achilles tendon. The low-volume plyometric CA (i.e., 3 sets of 5 repetitions) is recommended instead of high-loaded CA (≥85% one repetition maximum) for amateur athletes. In addition, it has been established that the performance improvement was independent of changes in the mechanical properties of the gastrocnemius medialis and Achilles tendon. Furthermore, it seems that the complexity of the post-CA task may affect the magnitude of the postactivation performance enhancement.

Acute Effects of Complex Conditioning Activities on Athletic Performance and Achilles Tendon Stiffness in Male Basketball Players.

The goal of this study was to compare the effects of a bilateral conditioning activity consisting of back squats and drop jumps with a unilateral one consisting of split squats and depth jumps to lateral hop over sequentially performed countermovement jump (CMJ), modified t-agility test (MAT), and Achilles tendon stiffness. Twenty-six basketball players participated in this study and were randomly and equally assigned to one of two different test groups: bilateral (B - CA) or unilateral (U - CA) conditioning activity group. The B - CA group completed 2 sets of 4 repetitions of back squats at 80% of one-repetition maximum (1RM), then 10 drop jumps, while the U - CA group performed 2 sets of 2 repetitions of split squats on each leg at 80%1RM, followed by 5 depth jumps to lateral hop on each leg as conditioning activity (CA) complexes. After a warm-up and 5 min before the CA the baseline Achilles tendon stiffness, CMJ, and MAT time measurement were performed. In the 6th min after the CA, all tests were re-tested in the same order. The two-way repeated measures mixed ANOVAs revealed that both B - CA and U - CA failed to produce significant improvements in CMJ and MAT performance. In addition, a significant increase in Achilles stiffness was demonstrated with both protocols (a main effect of time: p = 0.017; effect size = 0.47; medium). This study revealed that combining back squats and drop jumps, as well as split squats and depth jumps to a lateral hop, had no effect on subsequent CMJ and MAT performance in basketball players. Based on these results, it can be assumed that combinations of exercises, even if they have similar movement patterns, may cause excessive fatigue, resulting in no PAPE effect.

The Effect of Acute Caffeine Intake on Resistance Training Volume, Prooxidant-Antioxidant Balance and Muscle Damage Markers Following a Session of Full-Body Resistance Exercise in Resistance-Trained Men Habituated to Caffeine.

No previous study has analyzed the impact of caffeine intake on prooxidant-antioxidant balance and muscle damage following resistance exercise. The aim of this study was to determine the effect of 3 mg/kg of caffeine on the number of repetitions and the prooxidant-antioxidant balance and muscle damage after a session of full-body resistance exercise. Ten resistance-trained men habituated to caffeine participated in a randomized, crossover and double-blind experiment. Each participant performed two identical resistance training sessions after the intake of 3 mg/kg of caffeine or a placebo. Blood was collected before and 60 min after substance intake, just after exercise, 60 minutes after exercise, and 24 hours after testing to evaluate the activity of antioxidant enzymes (superoxide dismutase, glutathione peroxidase, catalase), non-enzymatic antioxidants (reduced glutathione, uric acid) levels of oxidative stress markers (plasma malondialdehyde) and muscle damage markers (creatine kinase, lactate dehydrogenase). There were no significant differences between placebo and caffeine conditions in the total number of repetitions (180 ± 15 vs 185 ± 14 repetitions, respectively; p = 0.276; Effect size [ES] = 0.34), the total time under tension (757 ± 71 vs 766 ± 56 s, respectively; p = 0.709; ES = 0.14) or the rating of perceived exertion (13.8 ± 2.7 vs 14.7 ± 2.7 a.u., respectively; p = 0.212; ES = 0.32). Reduced glutathione concentration obtained 1 hour after exercise was higher with caffeine than with placebo (p = 0.047), without significant difference between conditions for any other prooxidant-oxidant or muscle damage marker at any time point (p > 0.050 for all). The oral intake of 3 mg/kg of caffeine by resistance-trained men habituated to caffeine did not enhance the number of repetitions during a medium load full-body resistance training session to failure and had a minimal impact on the prooxidant-antioxidant balance and muscle damage. The study was registered prospectively at ClinicalTrials.gov with the following ID: NCT05230303.

Acute effects of two caffeine doses on bar velocity during the bench press exercise among women habituated to caffeine: a randomized, crossover, double-blind study involving control and placebo conditions.

PURPOSE: The main goal of this study was to evaluate the effectiveness of two different doses of caffeine (3 and 6 mg/kg) to enhance bar velocity during the bench press in women habituated to caffeine. METHODS: Twelve recreationally trained women (age: 23.3 ± 0.8 years, body mass: 60.7 ± 5.7 kg, bench press one-repetition maximum (1RM): 44.3 ± 7.8 kg, daily caffeine ingestion: 5.7 ± 2.0 mg/kg/day) participated in a randomized double-blind experimental design. Each participant performed four different experimental sessions: after no supplementation (control, CON), after ingesting 3 and 6 mg/kg of caffeine (CAF-3 and CAF-6, respectively), or after ingesting a placebo (PLAC). In each experimental session, the participants performed 3 sets of 3 repetitions of the bench press exercise at 50% 1RM. RESULTS: A two-way repeated-measures ANOVA with subsequent post hoc analyses indicated significant increases in peak velocity (p < 0.01; ES = 0.91) and mean velocity (p < 0.01; ES = 0.78) after the intake of CAF-6 compared to CON. The study did not show significant differences in bar velocity between CAF-6 and PLAC and between CAF-3 and PLAC. No significant differences in bar velocity were observed between CAF-3 and CAF-6 conditions. CONCLUSION: These results suggest that 6 mg/kg of caffeine can be an effective dose to improve power-specific training outcomes in women habituated to caffeine. However, the ergogenic effect of 6 mg/kg of caffeine may be derived from a combination of biological effects and expectancy, as this dose was only superior to the control condition with no differences over the placebo.

Postactivation Performance Enhancement of Concentric Bench Press Throw After Eccentric-Only Conditioning Exercise.

ABSTRACT: Krzysztofik, M, Wilk, M, Lockie, RG, Golas, A, Zajac, A, and Bogdanis, GC. Postactivation performance enhancement of concentric bench press throw after eccentric-only conditioning exercise. J Strength Cond Res 36(8): 2077-2081, 2022-This study examined changes in power output and bar velocity in the concentric-only bench press throw (CON ONLY ) after sets of eccentric-only bench press exercises (ECC ONLY ) at 2 supramaximal loads. Thirteen strength-trained men participated in this study (age = 25.7 ± 1.9 years, body mass = 94.8 ± 8 kg, 1 repetition maximum [1RM] = 147 ± 14.2 kg, and strength training experience = 6.5 ± 2.2 years). The subjects performed 2 conditioning sets of the bench press exercise of 2 repetitions each, with a 5-minute rest interval between sets, using the ECC ONLY mode against 110% or 130% of concentric 1RM load. The 1 repetition of the CON ONLY bench press throw with a load of 30% 1RM was performed before and 5 minutes after the conditioning activity (CA) to assess changes in peak power (PP) and peak velocity (PV). The differences between the analyzed variables before and after the CA were determined using a 2-way repeated measures analysis of variance. There was an increase of PP by 10.5 ± 6.0% (effect size [ES] = 0.34) and 9.9 ± 8.1% (ES = 0.33) for the 110 and 130% of concentric 1RM conditions, respectively, with no difference between the 2 conditions ( p < 0.01 main effect time, no interaction). Similarly, PV increased by 5.9 ± 5.5% (ES = 0.40) and 6.1 ± 6.1% (ES = 0.43) for the 110 and 130% of concentric 1RM conditions, respectively, with no difference between the 2 conditions ( p < 0.01 main effect time, no interaction). Activation with an ECC ONLY contraction and loads exceeding 1RM are effective at improving power output and bar velocity during the CON ONLY bench press throw.

Short-Term Blood Flow Restriction Increases Power Output and Bar Velocity During the Bench Press.

ABSTRACT: Wilk, M, Krzysztofik, M, Filip, A, Zajac, A, Bogdanis, GC, and Lockie, RG. Short-term blood flow restriction increases power output and bar velocity during the bench press. J Strength Cond Res 36(8): 2082-2088, 2022-This study examined the effect of blood flow restriction (BFR) with 2 different types of cuffs on peak power output (PP), mean power output (MP), peak bar velocity (PV), and mean bar velocity (MV) in the bench press exercise (BP). Fourteen healthy strength-trained male athletes (age = 27.6 ± 3.5 years; body mass = 84.1 ± 8.0 kg; height = 175.8 ± 6.7 cm; BP 1 repetition maximum [RM] = 138.6 ± 17.8 kg) performed 3 different testing protocols as follows: without BFR (NO-BFR), BFR with a narrow cuff (BFR NARROW ), and BFR with a wide cuff (BFR WIDE ) in a randomized crossover design. During all sessions, subjects performed one set of 3 repetitions of the BP exercise using 70% 1RM. Cuff pressure was set to approximately 90% full arterial occlusion pressure of the upper limb at rest. Analyses of variance showed an increase in PP (by 21%, p < 0.01; effect size [ES] = 1.67), MP (by 16%, p < 0.01; ES = 0.93), PV (by 22%, p < 0.01; ES = 1.79), and MV (by 21%, p < 0.01; ES = 1.36) during BFR WIDE compared with NO-BFR and a significant increase in PP (by 15%, p < 0.01; ES = 1.07), MP (by 17%, p < 0.01; ES = 0.78), PV (by 18%, p < 0.01; ES = 1.65), and MV (by 13% p < 0.01; ES = 1.00) during BFR WIDE compared with BFR NARROW . There were no significant differences in any of the variable between NO-BFR and BFR NARROW . The results of the study indicate that short-term BFR training increases power output and bar velocity during the BP exercise. However, only BFR WIDE significantly influenced bar velocity and power output, which indicates that the width of the cuff is a critical factor determining acute exercise adaptation during BFR resistance training.

Impact of movement tempo on bar velocity and time under tension in resistance exercises with different external loads.

The goal of the study was to determine the differences between volitional and maximal movement tempo during resistance exercise. Ten healthy men volunteered for the study (age = 26.4 ± 4.8 years; body mass = 93.8 ± 9.6 kg; barbell squat one-repetition maximum (1RM) = 175 ± 16.7 kg; bench press 1RM = 140.5 ± 26.8 kg). In a randomized order, the participants performed six sets of the barbell squat and the bench press exercise at progressive loads from 40% to 90%1RM (step by 10%) under two testing conditions: with volitional movement tempo or with maximal movement tempo. The three-way repeated measures ANOVA showed a statistically significant multi-interaction effect for time under tension (p < 0.001), peak bar velocity (p = 0.04) and for mean bar velocity (p < 0.001). There was also a statistically significant main effect of movement tempo for time under tension (p < 0.001), peak bar velocity (p < 0.001) and for mean bar velocity (p < 0.001). The post hoc analysis for main effect of tempo revealed that time under tension was significantly longer for volitional compared to maximal tempo (0.84 vs 0.67 s, respectively), peak bar velocity was significantly higher for maximal compared to volitional tempo (1.24 m/s vs 0.90 m/s, respectively), and mean bar velocity was significant higher for maximal compared to volitional tempo (0.84 m/s vs 0.67 m/s, respectively). The presented results indicate that there were significant differences between volitional and maximal movement tempos in time under tension and bar velocity (peak and mean), as well as significant differences in those variables between the two exercises. Therefore, the velocity of movement and time under tension is related to movement tempo, external load and type of exercise used.

Effects of Unilateral Conditioning Activity on Acute Performance Enhancement: A Systematic Review.

This review aimed to summarize the reported effects of unilateral conditioning activity (CA) on unilateral performance, bilateral performance, and the contribution of activated body limb to bilateral performance. A systematic search on MEDLINE, SPORTDiscus, Scopus, and Google Scholar was conducted on February 2022. Twenty-three studies met the inclusion criteria. Throwing, jumping, swimming, change of direction, and isokinetic performance were used as outcome measures to assess the impact of unilateral CAs on inducing post-activation performance enhancement. Eleven studies examined the effectiveness of resistance exercises as a CA, seven investigated plyometric exercises, and five used isokinetic muscle actions as CAs. Notably, only three studies directly compared the effects of bilateral and unilateral CA, and no study reported possible changes in the contribution of each limb during bilateral exercises executed following unilateral CA. Split squats were the most often studied CA (7), and it was shown that multiple sets of high-loaded split squats (85% one-repetition maximum) executed as CA, improve vertical jumping and change of direction after 4 to 8 min of recovery. At the same time, multiple sets of alternate leg bounds performed with ~10% body weight or without any external load result in an improvement of sprint performance, 2 and 8 min later, with the effect being greater when loaded jumps are used. The unilateral CAs such as split squats, alternate leg bounds, and drop jumps can be effectively used to acutely improve a wide variety of athletic tasks, including jumping, sprinting, change of direction, and swimming performance.

Acute impact of blood flow restriction on strength-endurance performance during the bench press exercise.

The main goal of the present study was to evaluate the acute effects of blood flow restriction (BFR) at 70% of full arterial occlusion pressure on strength-endurance performance during the bench press exercise. The study included 14 strength-trained male subjects (age = 25.6 ± 4.1 years; body mass = 81.7 ± 10.8 kg; bench press 1 repetition maximum (1RM) = 130.0 ± 22.1 kg), experienced in resistance training (3.9 ± 2.4 years). During the experimental sessions in a randomized crossover design, the subjects performed three sets of the bench press at 80% 1RM performed to failure with two different conditions: without BFR (CON); and with BFR (BFR). Friedman's test showed significant differences between BFR and CON conditions for the number of repetitions performed (p < 0.001); for peak bar velocity (p < 0.001) and for mean bar velocity (p < 0.001). The pairwise comparisons showed a significant decrease for peak bar velocity and mean bar velocity in individual Set 1 for BFR when compared to CON conditions (p = 0.01 for both). The two-way repeated measures ANOVA showed a significant main effect for the time under tension (p = 0.02). A post-hoc comparisons for the main effect showed a significant increase in time under tension for BFR when compared to CON (p = 0.02). The results of the presented study indicate that BFR used during strength-endurance exercise generally does not decrease the level of endurance performance, while it causes a drop in bar velocity.

The effects of resistance training experience on movement characteristics in the bench press exercise.

The main aim of this study was to determine whether the level of experience in strength training has a significant effect on differences in the value of exercise volume determined on time under tension (TUT) and number of repetition (REP) for a specific movement tempo. The study examined 68 men divided into groups of beginners and advanced strength trained athletes. The participants performed 5 sets of bench press (BP) at 70% 1RM using either a REG, MED or SLOW metronome guided cadence. Each set was performed to failure and with 3 min of rest between sets. Significant differences in TUT were found between the groups of beginners and advanced athletes for the slow (SLO) 6/0/4/0 tempo in set 1 (p = 0.01) and set 2 (p = 0.04), and for the regular (REG) 2/0/2/0 tempo in set 5 (p = 0.01). Significant differences were documented for total TUT between the beginners and advanced athletes for the SLO 6/0/4/0 tempo (p = 0.04). The results of ANOVA revealed significant differences in the number of repetitions between groups for the SLO 6/0/4/0 tempo in set 4 (p = 0.04) and set 5 (p = 0.04), and for the REG 2/0/2/0 tempo in set 5 (p = 0.01). The main finding of this study is that strength training experience has a significant effect on training volume, both in terms of TUT and REP at a specific constant movement tempo. Significant differences do not occur for each value of the tempo used.

Impact of Duration of Eccentric Movement in the One-Repetition Maximum Test Result in the Bench Press among Women.

Scientific studies related to resistance training have considered many variables; however, the tempo of movement of particular repetitions is often neglected or not reported in resistance training practice and research. The aim of the study was to determine the effect of different duration of the eccentric (ECC) phase of movement on one-repetition maximum test (1RM) results during the bench press exercise (BP). Twenty-one strength trained females (age = 23.4 ± 2.2 years, body mass = 52.3 ± 6.7 kg), with a minimum one year of strength training experience took part in the study. The experiment was conducted following a randomized crossover design, where each participant completed the 1RM test in the BP with three different duration times of the ECC movement: 2/0/X, 4/0/X, 6/0/X. Concentric (CON) movement was performed with maximal velocity (X). The ANOVA with repeated measures were used to compare the differences between the analyzed variables. The results of the study indicated the maximal load in the 1RM test was significantly higher during the BP with the 2/0/X tempo compared to 6/0/X (p < 0.01) and 4/0/X tempos (p < 0.01). Therefore, the results indicated that the longer the duration of the ECC phase of movement, the greater the decrease in the result of the 1RM test. The 1RM test procedure should include information about the movement tempo used during the test protocol.

The Effects of Eccentric Cadence on Power and Velocity of the Bar during the Concentric Phase of the Bench Press Movement.

Training at a specific movement tempo is a relatively new concept in resistance training. It is based on manipulation of the duration of particular phases of a movement. General studies have demonstrated that faster movement tempo in resistance training leads to an increase in muscle power, whereas lower movement speed is beneficial in the development of muscle strength and hypertrophy. However, the studies in this area are inconclusive and do not relate precisely to various tempos and movement speeds. The aim of the study was to determine the effect of duration of the eccentric cadence ECCREG (2/0/X/0) and ECCSLO (6/0/X/0) on muscular power generated in the concentric phase of the movement expressed in maximal PMAX, VMAX and average values PAVE, VAVE. For the ECCSLO (6/0/X/0) cadence, a significantly lower value of P (401.95 ± 65.42 W) was observed compared to the ECCREG 2/0/X/0 tempo (467.65 ± 79.18 W), at p = 0.007. The same was true for power evaluated in maximal values (PMAX), as significantly higher values were recorded for the regular ECCREG (2/0/X/0) (671.55 ± 115.79 W) compared to the slow tempo ECCSLO (6/0/X/0) (565,70 ± 117,37 W), at the level of significance of p = 0.007. The velocity evaluated for ECCREG (2/0/X/0) tempo expressed in average values (VAVE) 0.60±0.09 m/s was significantly higher compared to the ECCSLO (6/0/X/0) tempo (0.52 ± 0.08 m/s), with p=0.004. When maximal velocity (VMAX), was considered higher values for ECCREG (2/0/X/0) tempo was registered (0.79 ± 0.10 m/s) compared to the ECCSLO (6/0/X/0) tempo (0.69 ± 0.13 m/s), at significance of p = 0.001. The main finding of the study indicates that the duration of the eccentric phase of the movement has a significant impact on muscular power and velocity during the concentric phase of the movement.

Endocrine response to high intensity barbell squats performed with constant movement tempo and variable training volume.

OBJECTIVE: Research indicates that among the many elements of resistance exercise protocols, training volume and total training load are the key factors for post-exercise increase in the secretion of testosterone (T), growth hormone (GH), insulin-like growth factor (IGF-1) and cortisol (C). The aim of this study was to determine the effects of resistance exercises with variable volume and constant intensity and movement tempo on post-exercise concentrations of selected anabolic and catabolic hormones. MATERIALS AND METHODS: 28 experienced powerlifters (27.8 ± 2.9 years, with 6.64 ± 1.29 years of training experience, average body mass of 85.3 ± 3.3 kg and body height of 165.8 ± 10.3 cm) who compete at the national and international level performed three repetitions of barbell squats with a constant external load of 90% 1RM and variable volume (3, 6 and 12 sets of squats) in three stages (pre-exercise, immediately post exercise, and 1h after exercise) over three consecutive weeks. Venous blood samples (10ml) were collected from the antecubital vein, to determine pre- and post-exercise values of the following variables T, GH, IGF-1, C, at rest, immediately after the cessation of the last set of squats, and after 60 minutes of recovery. RESULTS: The T test showed that performing 6 and 12 sets resulted in increases of post exercise GH (p<0.01). Performing 6 sets of squats resulted in post exercise decrease (p<0.01) in IGF-1 and C. Performing 3 sets of squats resulted in immediate post exercise decrease of IGF-1 (p<0.01), which was not maintained 1h after exercise. There were no other significant differences in analysed variables, with the training volume of three sets of three repetitions, confirming previous data suggesting that low volume is the limiting factor in increased post-exercise secretion. CONCLUSION: This study demonstrated that in terms of endocrine response, the optimal volume of high intensity strength exercise is six sets. Therefore, intentionally high volume (12 sets) or low volume (3 sets) are not an effective stimuli for endocrine responses of trained individuals. The 6 sets of squats seems to drive hormonal responses of GH, C and IGF-1, which may play a significant role in stimulating muscle growth and tissue regeneration.

Endocrine responses following exhaustive strength exercise with and without the use of protein and protein-carbohydrate supplements.

The aim of this study was to determine the effect of carbohydrate-protein supplementation with whey protein (CHO-PROw) after resistance training, and casein protein (PROc) before bedtime on the concentration of growth hormone (GH), insulin (I) and insulin-like growth factor (IGF-1), as well as serum creatine kinase (CK) activity. Twelve strength trained male subjects (age: 25.8 ± 4.7 years; training experience 6.1 ± 0.79 years; body mass 75.9 ± 2.7 kg; body height 171.8 ± 13.3 cm) were recruited for the study. They were randomly divided into an experimental group (group E, n = 6) and a control group (group C, n = 6). All study participants completed full barbell squats with a constant external load of 90% one-repetition maximum (1RM) and a volume of 12 sets. In each set three repetitions were performed with 3 min rest periods after each set. Immediately after the exercise protocol, the subjects from the experimental group received a carbohydrate-protein complex (CHO-PROw) with a dose of 0.5 g/kg of body mass, while before bedtime they ingested a protein supplement (PROc) consisting of 90% casein protein with a dose of 0.3 g/kg of body weight The results indicate that a ignificant increase in GH concentration occurred in the experimental group between the pre-exercise level and after 24 h of recovery (p<0.01), as well as between 1 h and 24 hours of recovery (p<0.01). Significantly higher levels of GH were also found between the control group and the experimental group 24 hours after exercise (p<0.01). The results showed significantly higher levels of IGF-1 in the experimental than in the control group after 24 hours of recovery (p<0.05). In the case of insulin, no significant differences were observed when comparing levels before exercise, after exercise, after 1 hour of recovery and after 24 hours of recovery. The CHO-PROw and the PROc supplements did not reduce post-exercise muscle membrane damage as evidenced by serum CK activity. The intake of these supplements after high-intensity resistance exercise caused an increase in GH and IGF-1 concentration, which could stimulate muscle hypertrophy and inhibit proteolysis.