The Effects of Lateral Bounds on Post-Activation Potentiation of Change-of-Direction Speed Measured by the 505 Test in College-Aged Men and Women

Optimizing Post-activation Performance Enhancement in Athletic Tasks: A Systematic Review with Meta-analysis for Prescription Variables and Research Methods

BACKGROUND

Post-activation performance enhancement (PAPE) has demonstrated efficacy in acutely improving athletic performance. However, its distinction from general warm-up (GW) effects remains ambiguous, and experimental designs adopted in most PAPE studies exhibit important limitations.

OBJECTIVES

The aims of this work are to (i) examine the effects of research methodology on PAPE outcomes, (ii) explore PAPE outcomes in relation to comparison methods, performance measures, GW comprehensiveness, recovery duration, participants' characteristics, conditioning activity (CA) parameters, and (iii) make recommendations for future PAPE experimental designs on the basis of the results of the meta-analysis.

METHODS

Four databases were searched for peer-reviewed English-language literature. Risk of bias was assessed using a modified Cochrane Collaboration's tool and PEDro scale. PAPE groups were compared with control groups, pre-conditioning activity (pre-CA) performances were compared with post-conditioning activity (post-CA) performances throughout a verification test in PAPE groups, and control groups were compared before and after the "rest" period using a three-level meta-analysis. Further analyses, including subgroup analysis and both linear and nonlinear meta-regression methods, were used to explore the effect of different moderating factors on PAPE magnitude. A subgroup analysis of GW comprehensiveness was conducted using four classification methods. One method classified GW as non-comprehensive (stretching or jogging only), partially comprehensive (stretching, jogging, and low-intensity self-weighted dynamic exercises), and comprehensive (adding maximal or near-maximal intensity CAs to a partially comprehensive GW). The other three classifications were adjusted according to the type and number of GW exercises. Certainty of evidence was assessed using the GRADE approach.

RESULTS

The final analysis included 62 PAPE studies (1039 participants, male: n = 857, female: n = 182) with a high risk of bias and low certainty of pooled evidence. A trivial PAPE effect was observed from pre- to post-CA (effect size [ES] = 0.12, 95% CI [0.06 to 0.19], prediction intervals [PI] = - 0.29 to 0.54); a small PAPE effect was observed when compared with a control group (ES = 0.30, 95% CI [0.20 to 0.40], PI [- 0.38 to 0.97]). The slightly greater effect against control resulted from a small decrease in performance in control groups (ES = - 0.08, 95% CI [- 0.13 to - 0.03], PI [- 0.30 to 0.14]), but there was no relationship with between PAPE recovery time (β = - 0.005, p = 0.149). Subgroup analyses showed that PAPE magnitude was greater for non-comprehensive GWs (ES = 0.16) than comprehensive (ES = 0.01) and partially comprehensive GWs (ES = 0.11). In contrast, the control group showed a decline in performance after comprehensive GW (ES = - 0.20). An inverted U-shaped PAPE was noted as a function of recovery time. In some cases, PAPE appeared to manifest at < 1 min post CA. Additionally, participants with longer training experience (ES = 0.36) and higher training levels (ES = 0.38) had larger PAPE magnitudes. PAPE effect was higher in females (ES = 0.51) than males (ES = 0.32) and mixed groups (ES = 0.16) but did not reach a significant difference (p > 0.05). Plyometric exercise (ES = 0.42) induced greater PAPE amplitude than traditional resistance exercise (ES = 0.23), maximal isometric voluntary contraction (ES = 0.31) and other CA types (ES = 0.24).

CONCLUSIONS

Although the overall pooled results for both PAPE pre- versus post-CA and PAPE versus control group comparisons showed significant improvement, the wider and past-zero prediction intervals indicate that future studies are still likely to produce negative results. The comprehensiveness of the GW, the time between GW and the pre-CA test, participant sex, training level, training experience, type of CA, number of CA sets, and recovery time after CA all influence the PAPE magnitude. The PAPE magnitude was trivial after comprehensive GW, but it was greater in studies with a control group (i.e., no CA) because performance decreased over the control period, inflating the PAPE effect. Finally, two theoretical models of PAPE experimental design and suggestions for methodological issues are subsequently presented. Future studies can build on this to further explore the effects of PAPE.

PROTOCOL REGISTRATION

The original protocol was prospectively registered (osf.io/v7sbt) with the Open Science Framework.

Postactivation performance enhancement in the vertical jump using loads above or below the optimum-power load for a jump squat

BACKGROUND

Postactivation performance enhancement (PAPE) is an acute response of increased muscle performance following a conditioning activity (CA), generally prescribed based on the percentage of a one-repetition maximum. However, it is unknown how the PAPE response is affected when the CA is performed near the optimum power zone. The purpose of this study was to examine PAPE using loads that were 20% above or below the optimum-power load (OPL).

METHODS

Fifteen recreationally trained subjects, with at least one-year resistance training experience participated in this study. First, the OPL for the JS was determined. Then, subjects performed two protocols in a counterbalanced order: 20% above (+20%OPL) or below (-20%OPL). To examine PAPE on performance, the vertical jump was performed prior to and seven times following each jump squat protocol, with a 2-min rest interval between trials.

RESULTS

The two-way ANOVA revealed main effects for condition (F=4.978; P<0.001) for jump height and jump power (F=2.589; P=0.017), but post-hoc comparisons did not show differences. Between baseline and the best trial following each jump squat protocol, two-way ANOVA did not reveal main effects (F=3.048; P=0.103) or interactions (F=0.304; P=0.590). Paired t-tests did not show significant differences between conditions for relative changes in jump height (P=0.543) or jump power (P=0.233).

CONCLUSIONS

This study revealed similar results between 20% above or below the OPL on subsequent vertical jump performance.

Acute effects of prior conditioning activity on change of direction performance. A systematic review and meta-analysis

We performed a systematic review and meta-analysis on the acute effects of prior conditioning activity (CA) on change of direction (COD) performance. Eligible studies, involving healthy participants undergoing acute CA with at least one measure of COD performance, were analysed across diverse databases. A total of 34 studies were included for systematic review with 19 studies included for the meta-analysis. The intervention condition resulted in significantly faster (Z = 4.39; standard mean difference [SMD] = 0.49; p < 0.05) COD performance compared with the control condition. Both unloaded and light loaded CA resulted in significantly greater (SMD = 0.58-0.59) COD performance compared to the control condition. Moreover, heavy loaded CA demonstrated a significant but small (SMD = 0.24) improvement in COD performance compared to the control condition. Age and study design had no effect on the overall meta-analysis outcomes. Both males and females exhibited similar moderate effects with CA but only males demonstrated significantly greater COD performance compared to control conditions. Our findings indicate that a range of CA protocols can acutely improve COD performance with unloaded and light-loaded CA resulting in the greatest performance enhancements. These findings will assist practitioners with the design and implementation of appropriate acute CA to improve COD performance.

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.

A Preliminary Comparison of Firefighter Candidates' Biddle Physical Ability Test Performance and Success Based on Training Class Participation

The Biddle Physical Ability Test (BPAT) was developed to identify candidates who possess the physical ability to become structural firefighters. The test must be completed in ≤ 9:34 min:s before a candidate is admitted to an academy. Some community colleges offer semester-long training classes for candidates. This study analyzed whether candidates who completed a training class could perform the BPAT more effectively. Retrospective analysis of 30 males and 2 females who attempted the BPAT was conducted. BPAT tasks were: dry and charged hose drag; halyard raise, roof walk, and attic crawl; roof ventilation and victim removal; ladder removal and carry; stair climb with hose bundle; crawling search and tower exit; stair climb with air bottles; hose hoist; and return to ground floor with air bottles. Independent samples t-tests or Mann-Whitney U tests (p < 0.05) and effect sizes calculated BPAT time differences between candidates who completed a training class or not. Twenty-nine candidates passed the BPAT; 6 completed a training class. The 3 candidates (2 males, 1 female) who failed did not complete a class. There were no significant between-group differences in BPAT times (p = 0.054-0.829). There were moderate effects for faster roof ventilation and victim removal, ladder removal and carry, and hose hoist times for candidates who attended a class (d = 0.74-0.95). While training classes may not be necessary for all candidates, physically demanding BPAT tasks were finished faster by candidates who completed a class. For candidates who find the BPAT physicality difficult, participation in a task-specific fitness and skills class may prove beneficial.

Differences in Fitness between Firefighter Trainee Academy Classes and Normative Percentile Rankings

Fire academy training classes may have trainees with a range of different fitness capabilities. Documentation of trainee fitness could indicate the need for flexibility in physical training emphases. Therefore, data from six academy classes (males = 274; females = 31) were analyzed, including: Illinois agility test (IAT), push-ups, pull-ups, leg tucks, multistage fitness test, backwards overhead 4.54 kg medicine ball throw (BOMBT), 10-repetition maximum deadlift, and 18 kg kettlebell farmers carry. A one-way ANOVA, with the Bonferroni post hoc test, calculated between-class fitness differences. Normative fitness test data were produced via percentile ranks. Classes 5 and 6 had the most females (n = 15). Class 1 completed the IAT faster than all classes (p ≤ 0.009). Classes 1 and 4 had a further BOMBT distance than Classes 5 and 6, and Class 3 outperformed Class 6 (p ≤ 0.044). Class 4 completed more leg tucks than Class 5 (p = 0.047). Class 1 had a greater deadlift than Classes 3, 4, and 6, and Class 2 outperformed Classes 3–6 (p ≤ 0.036). Class 3 was slower in the farmers carry compared to all classes (p ≤ 0.002). Percentile rankings showed that most females (48–100%) were in the 0–29% rank. Staff should implement individualized programs where appropriate for trainees as cohort fitness differences exist. Female trainees may need targeted maximal strength and power development.

Extending Research on Law Enforcement Academy Graduation and Fitness: A Research Note on Receiver Operating Characteristic Curves

ABSTRACT

Lockie, RG, Dawes, JJ, Dulla, JM, and Orr, RM. Extending research on law enforcement academy graduation and fitness: A research note on receiver operating characteristic curves. J Strength Cond Res XX(X): 000-000, 2022-Fitness level contributes to a law enforcement recruit's ability to graduate from a training academy. However, limited research has used receiver operating characteristic (ROC) curves to ascertain whether fitness tests can accurately predict academy graduation. The investigators analyzed archival data from 311 recruits (260 males and 51 females) across 4 academy classes from 1 law enforcement agency. A robust, broad battery of fitness test data included grip strength for both hands, vertical jump, 75-yard pursuit run (75PR), 2-kg medicine ball throw, push-ups, sit-ups, arm ergometer revolutions in 60 seconds, and 20-m multistage fitness test (20MSFT) shuttles. Recruits were split into those who graduated (n = 269) or those who separated (did not complete academy; n = 42). A univariate ANOVA, with sex as a control variable, determined between-group fitness differences. Receiver operating characteristic curves were plotted for each fitness test, and the area under the curve (AUC) determined accuracy. Except for grip strength, graduated recruits were superior in all fitness tests (p < 0.001). The 75PR (AUC = 0.708) and 20MSFT (AUC = 0.727) had fair accuracy in predicting academy graduation. The data suggested that, ideally, fitness tests should not be used for diagnostic purposes in relation to academy graduation potential. Fitness test data can be used to provide specific feedback to at-risk recruits. These results suggest that the 75PR (change-of-direction speed) and 20MSFT (aerobic fitness) could contribute to successful graduation in law enforcement recruits. Law enforcement training staff could use this information to provide targeted training for recruits lacking in these qualities.

Fit (and Healthy) for Duty: Blood Lipid Profiles and Physical Fitness Test Relationships from Police Officers in a Health and Wellness Program

This research analyzed archival health and wellness program data (2018: 169 males, 39 females; 2019: 194 males, 43 females) to document police officer lipid profiles, and correlate lipids with fitness. Bloodwork included total cholesterol (TC), low-density lipoproteins (LDL-C), high-density lipoproteins (HDL-C), and triglycerides (TG). Fitness data included maximal aerobic capacity (V·O2max); sit-and-reach; push-ups; vertical jump; grip strength; sit-ups; and relative bench press (RBP). Lipid profiles were compared to national standards. Spearman’s correlations derived relationships between lipids and fitness (p < 0.05). Over 2018−2019, 68−76% of officers had desirable TC (<200 mg/dL) and HDL-C (≥60 mg/dL); 67−72% had desirable TG (<150 mg/dL). 54−62% of officers had LDL-C above desirable (≥100 mg/dL); 13−14% had mildly high TG (150−199 mg/dL); 16−18% had high TG (200−499 mg/dL). In 2018, HDL-C correlated with V·O2max, push-ups, grip strength, and RBP in males, and sit-ups in females. TG correlated with V·O2max (both sexes), sit-ups (males), and grip strength (females). In 2019, TG related to V·O2max, push-ups, vertical jump, sit-ups, and RBP in males. TG and LDL-C related to push-ups, and HDL-C to sit-ups and RBP in females. Relationship strengths were trivial-to-small (ρ = ±0.157 − 0.389). Most officers had good lipid profiles relative to cardiovascular disease risk. Nonetheless, the data highlighted the need for comprehensive approaches to decreasing risk.

The Effects Aerobic Fitness has on Heart Rate Responses for a Custody Assistant Recruit Class Performing a Formation Run

This study measured the heart rate (HR) responses to a formation run (group run completed along a set route) performed by higher fitness (HF), moderate fitness (MF), or lower fitness (LF) custody assistant (CA) recruits. Retrospective data from 26 recruits (12 males, 14 females) were analyzed. Prior to academy training, a YMCA step test was administered. Recruits were divided into three groups based on recovery HR: top 25% were HF; bottom 25% were LF; the rest were MF. Recruit HR was measured during a formation run completed at an ~11-minute mile · pace-1. HR zones were defined as: very light (< 57% of age-predicted maximum heart rate [HRmax]); light (57%-63% HRmax); moderate (64%-76% HRmax); vigorous (77%-95% HRmax); and very vigorous (> 95% HRmax). A one-way ANOVA, with Bonferroni post hoc, calculated between-group differences in time spent and percentage of total time in the HR zones during the run; effect sizes (d) were also calculated. HF recruits spent a significantly longer time and percentage of total time in the very light HR zone compared to the LF group (p ≤ 0.039; d = 1.20-1.35). There were no other significant between-group differences (p = 0.070-0.980). HF CA recruits spent more time in the very light training zone compared to the other groups (d = 0.92-1.35), which may not be optimal for aerobic adaptations. LF recruits spent more time in the vigorous-to-very vigorous HR zones (~45 minutes; 70% of the run). These recruits may potentially be working above their current capacity. Formation runs may not be the most efficient aerobic conditioning method for all CA recruits.

The Effects of the Barbell Hip Thrust on Post-Activation Performance Enhancement of Change of Direction Speed in College-Aged Men and Women

This study investigated whether the barbell hip thrust (BHT) enhanced change-of-direction (COD) speed measured by the 505 COD speed test. Forty recreationally trained individuals completed three sessions. Session 1 included one-repetition maximum (1RM) BHT testing to measure absolute and relative strength. Sessions 2 and 3 involved two counter-balanced conditioning activities (CAs): 3 sets × 5 repetitions of the BHT at 85% 1RM and a control condition (CC; 6 min rest). The 505 COD speed test was performed 5 and 2.5 min pre-CA, and 4, 8, 12, and 16 min post-CA in each session. A 2 × 5 repeated-measures ANOVA (p < 0.05) calculated performance changes across time post-CA. A 2 × 2 repeated-measures ANOVA analyzed best potentiated performance. Partial correlations controlling for sex calculated relationships between the 1RM BHT and 505 COD speed test percent potentiation. There was a significant main effect for time (p < 0.001), but not for condition (p = 0.271) or condition × time (p = 0.295). There were no significant correlations between 1RM BHT and potentiation. The 85% 1RM BHT did potentiate the 505 4–16 min post-CA but no more than the CC. Nonetheless, a heavy BHT could be programmed prior to COD drills as COD speed could be potentiated and performance improved in men and women.

We Need You: Influence of Hiring Demand and Modified Applicant Testing on the Physical Fitness of Law Enforcement Recruits

A challenge for law enforcement agencies is the many positions that need filling. Agencies may modify their applicant test battery (ATB; multilevelled testing including fitness, background checks, psychological evaluations) to increase the hiring pool of potential recruits by augmenting the utility of testing. This study determined fitness differences of law enforcement recruits hired under two different ATB protocols. Retrospective analysis was conducted on seven academy classes (442 males, 84 females) hired under an older ATB, and one class (45 males, 13 females) hired under a newer ATB. Recruits completed the following before academy: 60 s push-ups and sit-ups (muscular endurance); vertical jump (lower-body power); medicine ball throw (upper-body power); 75 yard pursuit run (75PR; change-of-direction speed); and 20 m multistage fitness test (20MSFT; aerobic fitness). Independent sample t-tests (p ≤ 0.001) and effect sizes (d) evaluated between-group fitness differences for recruits hired under the different ATB protocols (combined sexes, males, and females). There were no significant differences between the ATB groups. However, newer ATB female recruits completed 13% fewer 20MSFT shuttles than the older ATB group, which, although not significant (p = 0.007), did have a moderate effect (d = 0.62). Females hired under the newer ATB had lower aerobic fitness, which could impact physical training performance and graduation.

Physical Fitness, Sex Considerations, and Academy Graduation for Law Enforcement Recruits

Lockie, RG, Dawes, JJ, Dulla, JM, Orr, RM, and Hernandez, E. Physical fitness, sex considerations, and academy graduation for law enforcement recruits. J Strength Cond Res 34(12): 3356-3363, 2020-This study investigated the influence of fitness on academy graduation, and any between-sex differences, in law enforcement recruits. Data collected at the start of 4 training academies were retrospectively analyzed, including age, height, and body mass; waist circumference; waist-to-hip ratio; grip strength; vertical jump (VJ); 75-yard pursuit run; 2-kg medicine ball throw (MBT); push-ups, sit-ups, and arm ergometer revolutions in 60 seconds; and 20-m multistage fitness test (20MSFT) shuttles. Recruits were categorized into graduated (GRAD = 269) and separated (did not graduate; SEP = 42) groups. SEP recruits were not split according to separation reasons, just whether they did or not. This categorization also occurred for male subjects (GRAD = 228; SEP = 32) and female subjects (GRAD = 41; SEP = 10). Independent samples t-tests calculated between-group differences for all recruits combined, male subjects, and female subjects. Correlations and stepwise linear regression calculated relationships between the data and graduation. The t-test (p ≤ 0.016) and correlation (r = ±0.137-0.296; p < 0.05) data indicated that SEP recruits (both sexes combined) were older and performed poorer in every fitness test except grip strength and VJ. SEP male subjects were older and performed poorer in all tests except grip strength (p ≤ 0.009). SEP female subjects scored lower in the arm ergometer (p = 0.008). The regression equation for all recruits found that age, 20MSFT (aerobic fitness), MBT (upper-body power), and arm ergometer (upper-body endurance) were academy graduation predictors (r = 0.169; p < 0.001). For the male recruits, the predictors were age, MBT, and 20MSFT (r = 0.182; p ≤ 0.001), and for female recruits, arm ergometer and 20MSFT (r = 0.213; p ≤ 0.003). Recruits should improve multiple fitness aspects, including muscular endurance, power, and aerobic fitness, to enhance graduation potential.