Revisiting the 'Whys' and 'Hows' of the Warm-Up: Are We Asking the Right Questions?

Effects of Foam Rolling Prior to Proprioceptive Neuromuscular Facilitation Stretching on Hamstring Flexibility and Thigh Skin Temperature

CONTEXT

Proprioceptive neuromuscular facilitation stretching (PNFS) is suggested to improve the range of motion and flexibility as an active warm-up. Recently, the foam rolling (FR) methods have also emerged as a passive warm-up. However, the combined effects of PNFS and FR are still unclear, and no reports have compared their effects using thermal imaging. This study investigated the acute effects of combining nonvibration FR (NVFR) and vibration FR (VFR) prior to PNFS, in comparison with PNFS alone, on hamstring flexibility and thigh skin temperature.

DESIGN

Randomized controlled trial.

METHODS

Participants (n = 60) were randomly assigned to PNFS, NVFR + PNFS, VFR + PNFS, and control group (CG). Active knee-extension (AKE), sit and reach (SR) test, and thermal imaging were evaluated before (pre-int), immediately after (post-int), and 30-minutes after (post30-int) intervention.

RESULTS

All intervention groups had a significant increase at all time periods (P < .001) except the CG in terms of AKE and sit and reach test (P > .05). Combined (NVFR + PNFS/VFR + PNFS) groups had also a significant increase in the post30-int compared with pre-int and post-int values of thigh skin temperature (P < .001). Combined groups, over time, had the best post30-int effect on increasing skin temperature. The study found a significant interaction effect between interventions and time across several measurements (P < .05). Combined groups showed more significant improvements in AKE compared to CG at post-int (P < .05). There is a similar change in AKE, SR test, and skin temperatures between combined groups and PNFS alone at both post-int and post30-int (P < .05).

CONCLUSIONS

These findings indicate that using FR, with or without vibration, before PNFS does not provide an additional benefit in improving hamstring flexibility and thigh skin temperatures compared with PNFS alone.

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.

The Effect of Speed Endurance Versus Core Training on The Repeated Sprint Ability of Youth Male Soccer Players - A Randomized Controlled Trial

The effects of specific training protocols to improve repeated sprint ability are well known; however, the utility of non-specific training for this purpose is doubtful. Therefore, this study aimed to compare the effects of a specific (sport-related) vs. non-specific (general physical development) eight-week training protocol on developing or maintaining repeated sprint ability in soccer players. Thirty-eight male soccer players (aged 17.1 ± 0.3 years) were randomly divided into a speed endurance group (n = 18) and a core training group (n = 20). The speed endurance group performed 4 sprints lasting 15 seconds with a recovery of 75 seconds, while the core training group performed 2 sets of 4 exercises for 30 seconds with 15 seconds of recovery. Both protocols were performed twice a week. All players performed the Running-Based Anaerobic Sprint Test (6 consecutive 35-meter sprints with 10-seconds recovery intervals). A mixed two-way ANOVA was performed with no significant effects in the interaction term. On average, the speed endurance and the core training groups improved their repeated sprint ability by 7.9% and 8.0%, respectively, from pre- to post-assessment (p < 0.001, η2 p = 0.459). No significant between-group differences were detected for the Running-Based Anaerobic Sprint Test total time or maximum power. In principle, specific and non-specific low-volume training protocols may improve repeated sprint ability over eight weeks in soccer players. However, the improvements may have been derived from the continued soccer-specific training, which is the reason why future studies should include a passive control group and test whether high session volumes produce different results.

Acute responses to a potentiation warm-up protocol on sprint and change of direction in female football players: a randomized controlled study

OBJECTIVES

To evaluate the acute effect of exposure to a potentiation warm-up protocol compared to a usual warm-up program.

DESIGN

Randomized parallel control trial.

SETTING

Synthetic grass in the club's facilities (Portugal).

PARTICIPANTS

Seventeen female football players (age: 23.9 ± 3.9 years), were randomly allocated to a control (n = 8) and an experimental group (n = 9). To allocate the players, a table was computer-generated by a research team member with no involvement in the trial.

INTERVENTION

The control group performed their usual warm-up program, while the experimental group performed a potentiation warm-up protocol with jumps combined with sprints with change of direction.

MAIN OUTCOMES MEASURES

The players were tested pre- and post-intervention for a 40-m linear sprint and pre-planned change of direction using the T-test.

STATISTICAL ANALYSIS

An intention-to-treat analysis was performed, with all the participants originally randomized being involved. The normal distribution was verified by the Shapiro-Wilk test. The assumption of sphericity was analyzed. Effect sizes were calculated using partial eta squared.

RESULTS

No significant pre-post differences in the T-test and in the 40-m sprint were detected for any group. However, in the T-test, large effect sizes in time increments were observed within the experimental (0.27 s; p > 0.05, ηp2 = 0.176) and control groups (0.06 s; p > 0.05, ηp2 = 0.176). Also, in the 40-m sprint, large effect sizes in time increments were observed within the experimental (0.05 s; p > 0.05, ηp2 = 0.251) and control groups (0.09 s; p > 0.05, ηp2 = 0.251).

CONCLUSIONS

The performance-enhancing ability of the potentiation method performed at warm-up was not verified when applied to female football players. Thus, the potentiation methods may not improve sprint and COD ability for this population. However, the lack of statistical significance may have been due to reduced statistical power, as three of four effects suggest acute performance impairment after a supposed potentiation-oriented warm-up. Nevertheless, the presence of a statistical type 2 error cannot be ruled out.

REGISTRATION NUMBER (RETROSPECTIVELY REGISTERED)

NCT06555185; Project URL: https://clinicaltrials.gov/study/NCT06555185 .

Foam rolling and stretching do not provide superior acute flexibility and stiffness improvements compared to any other warm-up intervention: A systematic review with meta-analysis

BACKGROUND

Acute improvement in range of motion (ROM) is a widely reported effect of stretching and foam rolling, which is commonly explained by changes in pain threshold and/or musculotendinous stiffness. Interestingly, these effects were also reported in response to various other active and passive interventions that induce responses such as enhanced muscle temperature. Therefore, we hypothesized that acute ROM enhancements could be induced by a wide variety of interventions other than stretching or foam rolling that promote an increase in muscle temperature.

METHODS

After a systematic search in PubMed, Web of Science, and SPORTDiscus databases, 38 studies comparing the effects of stretching and foam rolling with several other interventions on ROM and passive properties were included. These studies had 1134 participants in total, and the data analysis resulted in 140 effect sizes (ESs). ES calculations were performed using robust variance estimation model with R-package.

RESULTS

Study quality of the included studies was classified as fair (PEDro score = 4.58) with low to moderate certainty of evidence. Results showed no significant differences in ROM (ES = 0.01, p = 0.88), stiffness (ES = 0.09, p = 0.67), or passive peak torque (ES = -0.30, p = 0.14) between stretching or foam rolling and the other identified activities. Funnel plots revealed no publication bias.

CONCLUSION

Based on current literature, our results challenge the established view on stretching and foam rolling as a recommended component of warm-up programs. The lack of significant difference between interventions suggests there is no need to emphasize stretching or foam rolling to induce acute ROM, passive peak torque increases, or stiffness reductions.

Do you even exercise, ref? Exploring habits of Spanish basketball referees during practice and matches

Background

Basketball referees are a vital part of the organised competition system, although they remain an "outgroup" in sport. While physical development and fitness programming are deemed necessary for basketball officiating excellence, there is a paucity of literature exploring strategies for physical fitness management in this population.

Methods

This research was a nationwide cross-sectional, self-administered online survey conducted in 2021. A sample of 628 (531 males, 97 females) referees from 18 regional referee organisations in Spain provided individual responses to gather information on demographic details, level of participation in refereeing, physical fitness practices, and match-day exercise-based regimens. The data were described using summary statistics, and the associations of the assessed variables were subsequently calculated using contingency tables.

Results

Our findings reveal that a large fraction of the Spanish basketball referee population focuses on aerobic (83%) and strength (73.6%) activities, while less attention is paid to speed (36.9%) and flexibility (23.2%), and agility, coordination, and balance tasks are somewhat overlooked. No significant differences were observed among the referee categories regarding weekly training days or session duration, with most training for 15-60 min per session. Elite referees were more likely to hire personal trainers and engage in strength and flexibility exercises. Sub-elite referees showed a higher tendency to perform stretching and joint mobility activities post-match, while regional referees did so less frequently. Approximately 30.7% of referees across all competitive levels engaged in re-warm-up (RW-U) activities, with stretching and joint mobility being the most prevalent.

Conclusions

Spanish basketball referees participate in routine physical exercise and fitness practices, irrespective of their competition level. While warm-up activities are prevalent, some sub-elite and regional referees do not consistently perform them, and re-warm-up routines are not extensively embraced.