Activity Profile and Between-Match Variation in Elite Male Field Hockey

High-Intensity Running During International Male Field Hockey Involves Frequent Changes of Direction and Repeated Accelerations but Seldom Reaches Sprint Velocities

ABSTRACT

Goods, PS, Appleby, B, Scott, BR, Peeling, P, and Galna, B. High-intensity running during international male field hockey involves frequent changes of direction and repeated accelerations but seldom reaches sprint velocities. J Strength Cond Res XX(X): 000-000, 2024-The aim of this investigation was to quantify the characteristics of high-intensity running in international male field hockey. Player movement data were collected through wearable player tracking devices across 3 tournaments (17 matches) from 27 members of the Australian male field hockey team (totaling 266 player matches). Active duration (minute), high-intensity efforts (>2.5 m·s-2 for >1 second), repeated high-intensity efforts (≥3 efforts with ≤45-second recovery between efforts), and sprints (>7 m·s-1) were extracted and aggregated for each player match. The duration, distance, mean and peak speed, mean change of direction and straightness for each high-intensity effort, and peak deceleration at the conclusion of each effort were calculated. Mixed-effects models were used to estimate the mean for each outcome (fixed effect), with random intercepts modeled for player and match. On average, players completed 42.2 high-intensity efforts and 2.1 sprints per match. High-intensity efforts were short (3.61 seconds, 12.9 m), failed to reach high velocities (average peak velocity: 4.8 m·s-1), and involved frequent changes of direction (56% of efforts were not straight). There were 4.7 bouts of repeated high-intensity efforts per player, per match (comprising 3.8 efforts, with 3.53 seconds per effort separated by 16.2-second recovery). Last, we also found that 29% of high-intensity efforts involved a high-speed deceleration (>3.5 m·s-2), and these occurred frequently when in conjunction with a >45° (86%) or >90° (89%) change of direction. We recommend practitioners focus on developing players' ability to repeatedly accelerate, decelerate, and change direction over short distances and adopt testing and monitoring programs that assess these qualities.

Wearable Sensors and the Evaluation of Physiological Performance in Elite Field Hockey Players

Sports performance tracking has gained a lot of interest and widespread use in recent years, especially in elite and sub-elite sports. This makes it possible to improve the effectiveness of training, to calibrate and balance workloads according to real energy expenditure, and to reduce the likelihood of injuries due to excessive physical stress. In this context, the aim of this review was to map the scientific literature on wearable devices used in field hockey, evaluating their characteristics and the available evidence on their validity in measuring physiological and movement parameters. A systematic investigation was carried out by employing five electronic databases and search terms that incorporated field hockey, wearables, and performance analysis. Two independent reviewers conducted assessments of the 3401 titles and abstracts for inclusion, and at the end of the screening process, 102 full texts were analyzed. Lastly, a total of 23 research articles that specifically concentrated on field hockey were incorporated. The selected papers dealt with performance monitoring (6 papers), technical analysis and strategy game (6), injury prevention (1), and physiological measurements (10). To appraise the quality of the evaluations, the Oxford quality scoring system scale was employed. The extraction of information was carried out through the utilization of the participants, intervention, comparison, and outcomes (PICOS) format. The analysis encompassed research studies that implemented wearable devices during training and competitive events. Among elite field hockey competitions, GPS units were identified as the predominant wearable, followed by heart rate monitors. The intraclass correlation coefficient (ICC) related to wearable devices showed reasonably high between-trial ICCs ranging from 0.77 to 0.99. The utilization of wearable devices in field hockey primarily centers around the measurement of player activity profiles and physiological demands. The presence of discrepancies in sampling rates and performance bands makes it arduous to draw comparisons between studies. Nevertheless, this analysis attested to the fact that wearable devices are being employed for diverse applications in the realm of field hockey.

Assessment of inter-individual variability in hamstring muscle recovery after a sport-specific sprint training in women and men

Background: Hamstring muscles are most affected by multiple sprint-based sports as a result of muscle strain during sprinting, leading to reduced performance and increased risk of injury. Therefore, the purpose of the study was to assess inter-individual variability in hamstrings recovery after a sport-specific repeated-sprint training (RST), through sprint-specific markers of muscle recovery and associated muscle damage biomarkers in women and men. Methods: Healthy females (n = 14) and males (n = 15) underwent 10 repeated 40-m sprints with a 3-min rest pause between each repetition. Force-generating capacity (FGC) by the 90° hip :20° knee test and range of motion Jurdan test, together with serum biomarkers [sarcomeric mitochondrial creatine kinase (sMtCK), oxidative stress, irisin] were tested at baseline and 24-, 48- and 72-h post-exercise through a repeated measures design. Participants were classified according to FGC loss into high responders (HR) and low responders (LR). Results: 21 individuals (10 females, 11 males) were classified as HR (FGC loss >20% and recovery >48 h), while 8 individuals (4 females, 4 males) were classified as LR. HR individuals showed unrecovered maximal voluntary isometric contraction (MVIC) torque until 72 h post-training (p = 0.003, np 2 = 0.170), whereas only HR males showed decreased range of motion (p = 0.026, np 2 = 0.116). HR individuals also showed increased sMtCK (p = 0.016, np 2 = 0.128), oxidative stress (p = 0.038, np 2 = 0.106) and irisin (p = 0.019, np 2 = 0.123). Conclusion: There is inter-individual variability in the muscular response to a sport-specific RST, identifiable by MVIC torque assessment. The findings support that the 90° hip :20° knee test is a powerful indirect test to screen hamstrings recovery in both women and men, in a cost-effective way. However, the Jurdan test might not be able to monitor hamstrings recovery in sportswomen after RST. Decreases in muscle capacity are linked to damage to muscle sarcolemma and mitochondria until 72 h post-exercise. Overall, 72 h will not be adequate time to restore hamstrings structure and function after a sport-specific RST in both female and male responders.

Sleep-push movement performance in elite field hockey champions with and without training specialization

Objective

To investigate kinematic and muscle activity differences during the sleep-push movement in elite field hockey players. We hypothesized that players with specialized sleep-push movement training (specialists) would possess a lower center of mass (CoM) and enhanced reproducibility of muscle activations during the movement, compared to players without explicit movement training (non-specialists).

Methods

Ten field hockey players of the Belgian national field hockey team performed the sleep-push movement (5 specialists and 5 non-specialists). Muscle activity and kinematic data were recorded using EMG to evaluate the reproducibility of muscle activations by cross-correlation analysis and power spectral features across the movement, while a motion capture system was used to assess kinematics.

Results

Compared to non-specialists, specialists had significantly (p < 0.05) increased stick velocity (9.17 ± 1.28 m/s versus 6.98 ± 0.97 m/s) and lower CoM height (141 ± 52 mm versus 296 ± 64 mm), during the second part of the shot. Specialists also showed a significant (p < 0.05) lower power spectrum in the activity of the upper limb muscles before the shot. Superimposition of the auto crosscorrelation results demonstrated a high degree of reproducibility in specialists' muscle activations.

Conclusion

Sleep-push movements realized by elite players who are specialists in the sleep-push movement presented significant kinematics and muscular activation differences when compared to the sleep-push movements realized by elite players who were not specialists in such movement. Characterization of the specific movement and the related high-level performer's muscular strategies offers the possibility of translating sport science findings into functional training with concrete applications for coaches, players, and other key stakeholders for the continued development of the field.

Physical preparation of the Australian national male field hockey team exceeded the movement demands of the Tokyo 2020 Olympic Games tournament

This investigation explored differences in the pre-tournament preparation period relative to the movement demands of the Tokyo 2020 Olympic Games for the Australian male field-hockey team. Movement data was collected over 7 months prior to and during the 13-day Olympic tournament. Duration, distance (total; >80% individual peak velocity; >5 m.s^-1), high-speed decelerations (>3.5 m.s^-2), and total accelerations and decelerations (>2.5 m.s^-2) were measured during each running-based session. A 13-day moving sum was calculated for each variable and compared to a player-specific "worst-case scenario" (WCS) for intra-tournament total movement demands. Summed 13-day movement demands exceeded the WCS for 6-58% of the preparation period across variables, for the entire squad. During the tournament, midfielders covered significantly greater sprint distance than Defenders (+84%,p = 0.020), with no other positional differences found. Greater variation in tournament movement demands was observed between players for accelerations, decelerations, and high-speed distance (CV = 19-46%) compared to duration and distance (CV = 4-9%). In conclusion, physical preparation exposed athletes to movement demands which surpassed WCS. Additionally, gross measures of training volume (duration and distance) are more generalisable to a squad; however, additional metrics such as sprint distance and high-speed decelerations are needed to better define positional and individual movement demands, and therefore, should be monitored by practitioners.

The Physical and Physiological Match-Play Locomotor Activity Profiles of Elite Domestic Male Field Hockey

A new four-quarter match format in field hockey has meant that the locomotor activity profiles of the sport are inconsistent with the literature. The aim of this investigation was to identify the physical and physiological demands of national-level male hockey players. Thirty-two male players participated in the study. Participants were monitored with GPS and heart rate monitors. Variables analysed were total time, total distance (m), relative total distance (m.min-1), total distance in velocity bands (m), and activity intensity (m.min-1). Mean and maximum heart rate were calculated as well as total time and percentage time spent in heart rate zones relative to HRmax. Players spent 52 ± 11 min in play. The total distance covered was 5986 ± 1105 m (116 ± 12 m.min-1) with 21.4 ± 6.8 m.min-1 of high intensity activity. Defenders covered the lowest relative total distance (p < 0.001) and attackers the highest (p < 0.001). Relative total distance in Q4 was 5% lower than in Q1and Q2 (p < 0.05) with moderate intensity exercise (8.1-15.5 km.h-1) being 11% lower in Q4 compared to Q1 and Q2. The mean HR and HRmax of players were 167 ± 10 and 194 ± 11 bpm respectively. Players had a lower mean HR in Q3 (164bpm) and Q4 (164bpm) compared to Q1 (169bpm) and Q2 (168bpm; p < 0.001). The current study provides novel data outlining the physical and physiological activity profiles of national-level male field hockey players across playing positions as well as quarters of play. The results highlight a need to consider positional differences when implementing a training programme for players at national level.

Characteristics of external loads of Hockey5s associated with the new version of U16 youth field hockey competition

External workloads associated Hockey 5 s, the new version of youth field hockey, were evaluated in 31 elite U16 male field players (15.4 ± 0.7 years) from three national teams. Mixed-longitudinal observations for the 31 players provided complete data for 33 forwards and 43 defenders. Activities of the players during games were monitored with the GPSports SPI Elite System with a sampling frequency of 10 Hz and were analysed with GPSports Team AMS (version R1 2015.14, Australia). Observed variables did not differ between forwards and defenders, and the three periods of play were differentiated only by maximal speed in the second and third periods. The greatest distances covered were in speed zone 3 (10.0-15.9 km h^-1; 35.5-38.2%) and the smallest in speed zones 4 (16.0-22.9 km h^-1; 14.8-15.6%) and 5 (> 23 km h^-1; 0.4-1.4%). The trends indicated high intensity levels for the entire match and by position and periods. Active time of forwards and defenders accounted for about one-half of a game's duration (~ 15.7 of 30 min). Overall, the Hockey 5s format was highly demanding of players and included relatively short intervals for recovery. The results emphasize the need for preparation that includes specific mixed anaerobic and aerobic training and also the importance of recovery during breaks.

The introduction of the six-again rule has increased acceleration intensity across all positions in the National Rugby League competition

The impact of the six-again rule change on the movement of National Rugby League (NRL) athletes was examined. Player Global Navigation Satellite System (GNSS) data (10 Hz) was collected from 42 athletes who competed in 56 matches across the 2019 to 2021 NRL seasons. Maximal mean speed (m·min^-1) and acceleration (m·s^-2) were established across a 10 s to 10-min duration via raw GNSS files, with subsequent intercept (mean estimates) and slope values determined via power law analysis. The distributions of match distance (m) and impulse (kN·s^-1) were established during ball-in-play time. To determine the significance between positions and seasons under different rules, linear mixed models were used. Effects were described using standardised effect sizes (ES) with 90% confidence limits (CL). Acceleration intercepts (power law-derived) across all positions were substantially greater (>0.6 SD) following the introduction of the six-again rule in the 2020 (mean ± SD; 1.02 ± 0.10 m·s^-2) and 2021 seasons (1.05 ± 0.08 m·s^-2) compared to the 2019 season (0.91 ± 0.07 m·s^-2). Mean acceleration during ball-in-play time was greater in 2020 (ES; 90% CL = 0.75; ± 0.32) compared to 2019. The acceleration requirements of rugby league increased across all positional groups following the modification in NRL competition rules. Practitioners should tailor training programs for athletes to reflect the increased acceleration intensity found under the revised competition format.

A repeated shuttle sprint test with female and male international field hockey players is reliable and associated with single sprint but not intermittent endurance performance

Field hockey is a high-intensity intermittent team sport that has recently undergone a series of rule changes that have resulted in a greater demand for repeated high-intensity movements. Coaches and practitioners now require a reliable assessment of repeated accelerations, decelerations and changes of direction to assess these important match qualities. This investigation assessed the test-retest reliability of a novel 6x40m repeated shuttle sprint test (20m + 20m with a 180° turn) and its association with 40m straight line sprint and YoYo Intermittent Recovery Test performance in 28 International field hockey players (n = 14 females and n = 14 males). The sum of 6 sprint times (SUM) demonstrated ‘excellent’ (ICC = 0.94 and CV = 0.59%) and ‘good’ (ICC = 0.84 and CV = 0.75%) reliability in females and males, respectively. Best sprint time during the repeated shuttle sprint test also demonstrated suitable reliability to evaluate field hockey physical performance (ICC = 0.92 & 0.76, CV = 0.76% & 1.00% in females and males, respectively). SUM was significantly associated with 40 m straight line sprint performance in females (r = 0.90; p<0.001) and males (r = 0.92; p<0.001), but only a weak association was found with YoYo Intermittent Recovery Test performance for either group (r = 0.20; p = 0.495 & r = -0.19; p = 0.525 in females and males, respectively). In summary, field hockey testing batteries that include a repeated shuttle sprint test should consider including a test of intermittent endurance. Further, changes in SUM greater than 1.0% can be confidently interpreted by coaches and practitioners as a real change for both female and male elite field hockey players.

Optimal relative workload for managing low-injury risk in lower extremities of female field hockey players: A retrospective observational study

ABSTRACT

Our study aimed to investigate the relative workload that is related to the injury in lower extremities of female field hockey players and to identify the optimal ratio of acute to chronic workloads (ACWR) depending on the playing position to manage low risk of sports-related injuries.Data were collected using a global positioning systems unit on a full-time basis and during competition among 52 players who were enrolled in Korea National Team. The ACWR was calculated by dividing the most recent 1 week workload by the prior 4 weeks workload. Injury risk was calculated for each category from very low to very high based on a z-score.In striker and midfielder, the injury risk was the lowest in the moderate-low category of total distance covered, meters per minute (MpM), repeated high-intensity effort bouts, and acceleration bouts, and the moderate-high category of high-intensity running distance (HID). The injury risk of a defender was the lowest in the moderate-low category of HID and MpM.The ACWR in total distance covered, MpM, repeated high-intensity effort bouts, and acceleration bouts should stay within the moderate-low category in striker and midfielder positions and HID and MpM in defender positions in order to manage low-risk of non-contact and soft tissue injuries in female field hockey players.

Quantifying Mean Peak Running Intensities in Elite Field Hockey

ABSTRACT

Delves, RIM, Bahnisch, J, Ball, K, and Duthie, GM. Quantifying mean peak running intensities in elite field hockey. J Strength Cond Res 35(9): 2604-2610, 2021-To replicate match demands in training, field hockey (FH) coaches typically prescribe intensities based on whole-match data. Such data may underestimate peak competition periods, potentially underpreparing athletes for competition. This study then aimed to quantify maximal mean running intensities during elite FH competition to facilitate enhanced training prescription. Ten-Hertz Global Positioning System data were collected from 17 male and 11 female FH athletes who competed in the 2016 and 2017 Australian Hockey League tournaments. Maximal mean values for speed, acceleration, and metabolic power (Pmet) were calculated over a 1- to 10-minute moving average by position. Summary match statistics were also analyzed. Linear mixed models were constructed to determine the effect of position on moving average and summary variables. Pairwise comparisons between groups were made using magnitude-based inferences. In female competition, speed and Pmet intensities were greater in midfielders, whereas defenders were lowest in acceleration demands over the 10-minute window and in corresponding intercepts. In male competition, acceleration was greater in defenders during the 10-minute window and in subsequent intercepts compared with midfielders, whereas defenders were lowest in speed intercepts. In comparison with previously reported summary match variables, intensities from the 1-minute moving average interval were 50-65% greater in male competition and 30-50% greater in female competition. The 10-minute moving average framework has identified FH running intensities that are greater than previously reported whole-match averages. This information enhances the understanding of the demands of FH, assisting practitioners to prepare their athletes for the most demanding instances of play.

Effect of Changing Match Format from Halves to Quarters on the Performance Characteristics of Male University Field Hockey Players

The study examined whether the performance characteristics of male university field hockey players differed when the match format was 2 × 35 min halves compared to 2 × 2 × 17.5 min quarters. Thirty-five male university field hockey players (age 21.2 ± 3.0 years, height 1.81 ± 0.07 m, body mass 75.1 ± 8.9 kg), competing at national level in the UK, were monitored over 52 matches played across the 2018–2019 (2 × 35 min halves) and 2019–2020 (2 × 2 × 17.5 min quarters) seasons using 15 Hz Global Positioning System units and heart rate monitors. Total distance, high-speed running distance (≥15.5 km·h⁻¹), accelerations (≥2 m·s⁻¹), decelerations (≤−2 m·s⁻¹), average heart rate and percentage of time spent at >85% of maximum heart rate were recorded during both match formats. Two-level random intercept hierarchal models (Match—level 1, Player—level 2) suggested that the change in format from 2 × 35 min halves (2018–2019 season) to 2 × 2 × 17.5 min quarters (2019–2020 season) resulted in a reduction in total distance and high-speed running distance completed during a match (by 221 m and 120 m, respectively, both p < 0.001). As no significant cross-level interactions were observed (between season and half), the change from 35 min halves to 17.5 min quarters did not attenuate the reduced physical performance evident during the second half of matches (total distance: −235 m less in second half; high-speed running distance: −70 m less in second half; both p < 0.001). Overall, the findings suggest that the change in match format did alter the performance characteristics of male university field hockey players, but the quarter format actually reduced the total distance and high-speed running distance completed during matches, and did not attenuate the reduction in performance seen during the second half of matches.

Wearable Technologies in Field Hockey Competitions: A Scoping Review

The aim of this review is to investigate the common wearable devices currently used in field hockey competitions, and to understand the hockey-specific parameters these devices measure. A systematic search was conducted by using three electronic databases and search terms that included field hockey, wearables, accelerometers, inertial sensors, global positioning system (GPS), heart rate monitors, load, performance analysis, player activity profiles, and competitions from the earliest record. The review included 39 studies that used wearable devices during competitions. GPS units were found to be the most common wearable in elite field hockey competitions, followed by heart rate monitors. Wearables in field hockey are mostly used to measure player activity profiles and physiological demands. Inconsistencies in sampling rates and performance bands make comparisons between studies challenging. Nonetheless, this review demonstrated that wearable devices are being used for various applications in field hockey. Researchers, engineers, coaches, and sport scientists can consider using GPS units of higher sampling rates, as well as including additional variables such as skin temperatures and injury associations, to provide a more thorough evaluation of players’ physical and physiological performances. Future work should include goalkeepers and non-elite players who are less studied in the current literature.

Peak Running Intensities in Field Hockey - A Positional Analysis

The aim of this study was to investigate the positional mean peak running periods during a field hockey match using a moving average method. The secondary aim was to investigate how the peak periods changed between quarters and playing positions. The moving average method was used to analyse the data because of the nature of field hockey, which has natural fluctuations of high and low intensity periods of play. The time periods included periods from 1 to 10 minutes. The level of significance for results was set at p ≤ 0.05. The study found that forwards had a peak running intensity of 194 ± 24.2 m·min^-1, midfielders 189 ± 11.9 m·min^-1, and defenders 182.6 ± 17.9 m·min^-1. These results showed that forwards had the highest maximum running speed, with defenders having the lowest one (p = 0.0025). Additionally, running output started to plateau after 7/8-min periods for each of the three positions. Forwards did not show any statistically significant changes across the four quarters. Midfielders showed effect sizes ranging from >0.6 to >2.0 (moderate, large and very large) significance when comparing the first three quarters to the fourth one. Defenders showed >0.6 to <2.0 (moderate to large) effect sizes to occur when comparing the first and second quarter to the fourth. There are three main practical implications from the results of this study: 1) the creation of conditioning drills, 2) substitution patterns, and 3) knowledge to be able to plan and train at or above peak match demands.

Deceleration characteristics of elite Australian male field hockey players during an Olympic tournament

OBJECTIVES

This study described the deceleration efforts of the Australian men's field hockey team during the 2016 Olympics by categorising efforts into 'bands' of intensity; and comparing the deceleration intensity and frequency by player position, game period and opponent.

DESIGN

Descriptive retrospective analysis.

METHODS

Global positioning system sensors (MinimaxX S4, Catapult Sports Pty. Ltd., Melbourne, Australia; 10Hz) were worn by 15 male field hockey players during six games of the 2016 Olympic tournament.

RESULTS

There were 8998 individual deceleration efforts (≤-3ms^-2) performed over the tournament with the most intense effort measured at -13.6ms^-2. Deceleration intensity 'bands' were calculated using Receiver Operator Characteristic (ROC) curves as low intensity=-3 to -5.99ms^-2; medium intensity=-6 to -8.99ms^-2; high intensity=-9 to -11.99ms^-2; and, very high intensity=<-12ms^-2. There were no significantly different decelerations between field positions but decelerations performed within game period one were more intense than game period two (-0.11±0.01ms^-2, p<0.001). Deceleration efforts were more frequent in game period one than two [X²(3, N=8997)=12.00, p=0.007].

CONCLUSIONS

Decelerations are common in elite field hockey and very high intensities are present. These findings, in conjunction with other metrics can be used as a tool to monitor the load associated with training and match play in field hockey.

Positional Comparisons in the Impact of Fatigue on Movement Patterns in Hockey

PURPOSE

To examine the influence of the match period on the movement patterns of hockey players according to their playing positions under the introduction of quarters (QTRs).

METHODS

Sixteen subelite-level Spanish National League male hockey players participated in the study (age: 25.5 [2.9] y; body mass: 74.6 [5.5] kg). Global positioning system devices were used to monitor players' running performance during 17 competitive matches (113 match-play profiles). Only players who played for at least 85% of the game were analyzed. Players were placed into 3 position categories: backs, midfielders, and forwards.

RESULTS

Moderate to large differences in relative total distance were found between midfielders and both backs and forwards in all QTRs (effect size [ES]: 0.4-1.2). ES for total distance was moderate for midfielders when compared with backs during the first QTR (moderate ES: 0.7). Midfielders and forwards covered more distance (m and m·min^-1) in high-velocity zones than backs (ES: 0.6). Acceleration activities (n·min^-1) at moderate and high intensities decreased in all groups across QTRs with moderate to very large ES (ES: 0.4-1.4). Relative sprinting distance decreased in backs (ES: 0.8). Backs had fewer repeated-sprint bouts (n and n·min^-1) as the game progressed (ES: 1.0).

CONCLUSIONS

During competitive match play, a degree of positional variation can be observed across QTRs. The relative distance and the number of accelerations and decelerations at moderate and high intensity decreased across QTRs. No between-QTRs differences in high-speed activity were reported.

Sodium bicarbonate supplementation does not improve elite women's team sport running or field hockey skill performance

Team sports, such as field hockey, incorporate high-intensity repeated sprints, interspersed with low-intensity running, which can result in acidosis. The aim of the present study was to examine the effect of acute sodium bicarbonate (SB) supplementation on team sport running and skill performance. Eight elite female field hockey players (age 23 ± 5 years, body mass 62.6 ± 8.4 kg, height 1.66 ± 0.05 m) completed three Field Hockey Skill Tests (FHST) interspersed with four sets of the Loughborough Intermittent Shuttle Test (LIST). Prior to exercise, participants were supplemented with capsules equivalent to 0.2 g·kg-1 body mass (BM) of a placebo (maltodextrin) or 0.3 g·kg-1 BM SB. Field hockey skill performance incorporated overall performance time (PFT), movement time (MT), decision-making time (DMT), and penalty time (PT). Sprint time (ST), rating of perceived exertion (RPE), blood lactate concentration, bicarbonate anion ( HCO 3 - ) concentration, pH, and base excess were measured at various time points. Data (mean ± SD) were analyzed using a two-way analysis of variance (ANOVA) with repeated measures, with Hedges g effect sizes used to interpret the magnitude of differences. Bicarbonate anion concentration (+5.4 ± 2.6 mmol·L-1 ) and pH (+0.06 ± 0.03) were greater during the bicarbonate trial compared with the placebo (P < 0.001). Bicarbonate did not alter PFT (placebo: 87.9 ± 6.9 sec; bicarbonate: 89.0 ± 7.8 sec, P = 0.544, g = 0.14), MT, DMT, PT (all P > 0.30) or ST (placebo: 2.87 ± 0.12 sec; bicarbonate: 2.86 ± 0.12 sec, P = 0.893, g = -0.08). RPE was lower during the SB condition (placebo: 13 ± 2; bicarbonate: 12 ± 2, P = 0.021, g = -0.41). Acute ingestion of bicarbonate did not improve sprint or sport-specific skill performance. Bicarbonate ingestion did result in a lower perception of effort during team-sport running, which may have performance implications in a competitive match situation.

The within-participant Correlation between s-RPE and Heart Rate in Youth Sport

The monitoring of training load is important to ensure athletes are adapting optimally to a training stimulus. Before quantification of training load can take place, coaches must be confident that the tools available are accurate. We aimed to quantify the within-participant correlation between the session rating of perceived exertion (s-RPE) and summated heart rate zone (sHRz) methods of monitoring internal training load. Training load (s-RPE and heart rate) data were collected for rugby, soccer and field hockey field-based training sessions over a 14-week in-season period. A total of 397 sessions were monitored (rugby n=170, soccer n=114 and field hockey n=113). Within-subject correlations between s-RPE and sHRz were quantified for each sport using a general linear model. Large correlations between s-RPE and the sHRz method were found for rugby (r=0.68; 95% CI 0.59-0.75) and field hockey (r=0.60; 95% CI 0.47-0.71) with a very large correlation found for soccer (r=0.72; 95% CI 0.62-0.80). No significant differences were found between the correlations for each sport. The very large and large correlations found between s-RPE and the sHRz methods support the use of s-RPE in quantifying internal training load in youth sport.