TABLE 4.

Methodological characteristics of the included studies.

Study	Objective of research	Tests used for individualization	Method of individualization	Arbitrary thresholds used	Individualized thresholds used
Abbott et al. [51]	Analyze the differences between arbitrary and individualized acceleration thresholds in training sessions and matches	40-m linear sprint	Maximum rate of acceleration during 40-m linear sprint	Low-intensity acceleration (1–2 m/s2); Moderate-intensity acceleration (2–3 m/s2); High-intensity acceleration (> 3 m/s2).	Low-intensity acceleration (25–50% of maximal acceleration); Moderate-intensity acceleration (50–75% of maximal acceleration); High-intensity acceleration (> 75 of maximal acceleration).
Abt et al. [26]	Compare arbitrary and individualized speed thresholds on locomotor outcomes in matches	Incremental treadmill test	The 2nd ventilatory threshold was used to determine the point of high intensity speed threshold.	High intensity running (distances covered at > 19.8 km/h)	High intensity running (2nd ventilatory threshold)
Beato et al. [57]	Analyze the workload of professional soccer players using arbitrary and individualized outcomes	Peak speed registered in training sessions/ matches	Peak speed attained in training sessions/matches	Distance covered above 20 km/h Distance covered above 25 km/h	High-speed distance (80% MSS)
Carling et al. [75]	Analyze the variability of locomotor demands between matches	Incremental treadmill test	MAS was determined and used to classify match activities	Total high-speed running distance (average running speed ≥ 19.8 km/h); High speed running distance (average running speed from 19.8 to 25.2 km/h); Total sprint distance (average running speed > 25.2 km/h).	Between 80–100% MAS; > 100% MAS; ≥ 80% MAS.
Casamichana et al. [76]	Compare arbitrary and individualized speed thresholds on locomotor outcomes in matches	Peak speed in match	Peak speed attained during the season (in match)	Moderate speed running (15.1–18.9 km/h); High speed running (> 19 km/h); Very high speed running (> 24 km/h); Sprint running (> 30 km/h).	Distances covered at ~30%, 50%, 60%, 75% and 95% of the average peak speed of the players.
Castellano et al. [77]	Analyze the influence of different small-sided games on locomotor and physiological outcomes in small-sided games	30-m linear sprint	Individualized to MSS	Distance at 0–3 km/h; Distance at 3–8 km/h; Distance at 8–13 km/h; Distance at 13–16 km/h; Distance at > 16 km/h.	Distance at > 40% MSS; Distance at 40–60% MSS; Distance at > 60% MSS.
Castellano et al. [78]	Analyze the influence of different small-sided games on locomotor and physiological outcomes in small-sided games	30-m linear sprint	Individualized to MSS	Distance at 0–3 km/h; Distance at 3–8 km/h; Distance at 8–13 km/h; Distance at 13–16 km/h; Distance at > 16 km/h.	Distance at > 40% MSS; Distance at 40–60% MSS; Distance at > 60% MSS.
Clarke et al. [38]	Compare arbitrary and individualized speed thresholds on locomotor outcomes in matches	Incremental treadmill test	The 2nd ventilatory threshold was estimated and used for the individualization of high intensity running.	High intensity running (5 m/s); High intensity running (group mean 2nd ventilatory threshold); Low-speed running (< 2 m/s); Sprint (acceleration at > 2.5 m/s2 for a minimum of 1 second).	High intensity running (individualized to the 2nd ventilatory threshold)
Darbellay et al. [43]	Compare arbitrary and individualized speed thresholds on locomotor outcomes in small-sided games and matches	Yo-Yo Intermittent RecoveryTest level 1 and 40-m linear sprint	The MAS was obtained from the latest stage achieved in the progressive running test, while the ASR was estimated based on the difference between MSS and the MAS. Additionally, the metabolic power (resulted from speed and acceleration data) was also used as individualized method.	Low intensity (0 to 8 km/h); Moderate intensity (8 to 13 km/h); Intermediate speed (13 to 16 km/h); High intensity (16 to 19 km/h); Very high intensity (> 19 km/h).	Low intensity (0 to 60% MAS or 0 to 10 W/kg metabolic power zone); Moderate intensity (60 to 80% MAS or 10 to 15 W/kg metabolic power zone); Intermediate speed (80 to 100% MAS or 15 to 20 W/kg metabolic power zone); High intensity (100% MAS to 30% ASR or 20 to 35 W/kg metabolic power zone); Very high intensity (> 30% ASR or > 35 W/kg metabolic power zone).
Fitzpatrick et al. [11]	Compare dose-response relationship between arbitrary and individualized speed threshold with changes in aerobic fitness	1500-metre time trial and 40-m linear sprint	The MAS was obtained from the 1500-metre time trial, while the ASR was estimated based on the difference between MSS and the MAS.	High speed distance (above 17 km/h) - match to group average of MAS; High speed distance (above 21 km/h) - match to group average of 30% ASR.	Meters covered above MAS; Meters covered above 30% ASR.
Gabbett et al. [45]	Compare arbitrary and individualized speed thresholds on locomotor outcomes in matches	40-m linear sprint	The MSS in the interval of 20-40-linear sprint test was obtained to estimate the peak velocity.	Low speed (0-3.5 m/s); Moderate speed (3.6-5.0 m/s); High speed (> 5.0 m/s).	Low speed (0-25% MSS); Moderate speed (25-50% MSS) High speed (50-70% MSS); Very high speed (> 70% of the peak velocity).
Gamble et al. [79]	Compare arbitrary and individualized speed thresholds on locomotor outcomes in matches	Peak speed in match	Peak speed attained during the season (in match)	1.0–10.9 km/h; 11.0–13.9 km/h; 14.0–16.9 km/h; 17.0–20.9 km/h; 21.0–24.0 km/h; > 24 km/h	< 20% of the peak speed; 20-39% of the peak speed; 40–59% of the peak speed; 60–79% of the peak speed; 80–90% of the peak speed; > 90% of the peak speed.
Goto et al. [80]	Compare arbitrary and individualized speed thresholds on locomotor outcomes in matches	10-m linear sprint	The flying 5-m linear sprint time was used to estimate the MSS and to split into five equal individualized speed zones	Speed zone 1 (0.0-0.5 m/s); Speed zone 2 (1.6-3.0 m/s); Speed zone 3 (3.1-4.5 m/s); Speed zone 4 (4.6-6.0 m/s); Speed zone 5 (> 6.0 m/s).	Speed zone 1 (slowest: 0.0–1.1 m/s; fastest 0.0–1.5 m/s); Speed zone 2 (slowest: 1.2–2.2 m/s; fastest 1.6–3.0 m/s); Speed zone 3 (slowest: 2.3–3.3 m/s; fastest 3.1–4.5 m/s); Speed zone 3 (slowest: 3.4–4.4 m/s; fastest 4.6–6.0 m/s); Speed zone 3 (slowest: > 4.4 m/s; fastest > 6.0 m/s).
Hunter et al. [19]	Compare arbitrary and individualized speed thresholds on locomotor outcomes in matches	Incremental treadmill test and 40-m linear sprint	MAS and the RCT were obtained from the incremental treadmill test and were used as measures for individualization. The MSS was obtained in the fastest 10-m split. The ASR resulted from the subtraction of MSS by the MAS.	Low speed running (< 14.99 km/h); High-speed running (15.0-17.99 km/h); Very-high speed running (18.0-24.99 km/h); Sprinting (25.0-35.0 km/h).	Low speed running (< RCT or < 79%MAS; or < 49%MSS; or < 79% MAS); High-speed running (RCT-95% of maximal oxygen uptake; or 80-99% MAS; or 50-59% MSS; or 80-99% MAS); Very-high speed running (95% of maximal oxygen uptake-29% ASR; or 100-139% MAS; or 60-79% MSS; or 100% MAS-29% ASR); Sprinting (30% ASR-MSS; or 140% MAS-35 km/h; or 80-100% MSS; or 30% ASR-MSS)
Jastrzebski et al. [39]	Compare arbitrary and individualized speed thresholds on locomotor outcomes in small-sided games	Incremental treadmill test and 40-m linear sprint	The lactate threshold was estimated during the incremental treadmill test, while applying the Dmax method. The MSS was determined in the 40-m linear sprint.	Standing, walking (0-2 m/s); Jogging (2-4 m/s); Running (4-5.5 m/s); High-speed running (5.5-7 m/s); Sprinting (> 7 m/s).	Walking (0-1 m/s); Walking, jogging (1-2 m/s); Low intensity running (2 m/s-lactate threshold); High-intensity running (lactate threshold-80%MSS); Sprinting (> 80% MSS).
Jastrzebski et al. [40]	Compare arbitrary and individualized speed thresholds on locomotor outcomes in small-sided games	Incremental treadmill test and 40-m linear sprint	The lactate threshold was estimated during the incremental treadmill test, while applying the Dmax method. The MSS was determined in the 40-m linear sprint.	Standing, walking (0-2 m/s); Jogging (2-4 m/s); Running (4-5.5 m/s); High-speed running (5.5-7 m/s); Sprinting (> 7 m/s).	Walking (0-1 m/s); Walking, jogging (1-2 m/s); Low intensity running (2 m/s-lactate threshold); High-intensity running (lactate threshold-80%MSS); Sprinting (> 80% MSS).
Lovell et al. [41]	Compare arbitrary and individualized speed thresholds on locomotor outcomes in match	Incremental treadmill test	The 1st ventilatory threshold, the RCT and MAS were estimated during the incremental treadmill test.	High-speed running (> 14.4 km/h); Very-high speed running (> 19.8 km/h).	Low (< 1st ventilatory threshold); Moderate (1st ventilatory threshold-RCT); High (RCT-MAS).
Martínez-Cabrera et al. [49]	Compare arbitrary and individualized speed thresholds on high-intensity acceleration in match	40-m linear sprint starting from standing, 6, 10.8 and 15 km/h	The maximal acceleration attained in the 40-m linear sprint test was used for the individualization.	High-intensity acceleration (> 3 m/s2).	High-intensity acceleration (> 75% maximal acceleration).
Martínez-Cabrera et al. [50]	Compare arbitrary and individualized speed thresholds on high-intensity acceleration in match	40-m linear sprint starting from standing, 6, 10.8 and 15 km/h	The maximal acceleration attained in the 40-m linear sprint test was used for the individualization.	High-intensity acceleration (> 3 m/s2); High-intensity acceleration (> 4 m/s2).	High-intensity acceleration (> 75% maximal acceleration & > 21 km/h); High-intensity acceleration (> 75% maximal acceleration).
Massard et al. [81]	Compare arbitrary and individualized speed thresholds regarding the impact on workload measures and non-contact injury	40-m linear sprint starting or peak speed attained in match demands (players not assessed for 40-m sprint) and 30-15 Intermittent Fitness test for MAS	The final velocity achieved at 30-15 Intermittent Fitness test was used as reference for the high-speed running individualized threshold.	High-speed running (19.8 km/h or 5.5 m/s2).	High-speed running (> MAS)
Murray et al. [44]	Compare arbitrary and individualized speed thresholds regarding the impact on injury likelihood and workload measures	Peak speed attained in training demands	The average MSS (32.1 km/h) was used as reference to create the relative thresholds for each speed zone.	Low (< 6 km/h); Moderate (6-18 km/h); High (18-24 km/h); Very high (> 24 km/h).	Low (0-19.99% MSS); Moderate (20-54.99% MSS); High (55-74.99% MSS); Very high (> 75% MSS).
Nakamura et al. [52]	Compare arbitrary and individualized speed thresholds on sprinting and repeated-sprints in matches	20-m linear sprint	Mean speed over 20-m linear sprint was used as MSS.	Sprint (> 20 km/h)	Sprint (> 90% MSS)
Núñez-Sánchez et al. [82]	Compare arbitrary and individualized speed thresholds on locomotor demands in matches	40-m linear sprint	The MSS obtained in the 40-m linear sprint was used for the individualization process.	Very low intensity running (0-7 km/h); Low intensity running (7-13 km/h); Medium intensity running (13-18 km/h); High intensity running (18-21 km/h)	< 10% MSS; 10-20% MSS; 20-30% MSS; 30-40% MSS; 40-50% MSS; 50-60% MSS; 60-70% MSS; 70-80% MSS; 80-90% MSS; > 90% MSS.
O’Connor et al. [56]	Compare arbitrary and individualized speed thresholds regarding the impact on non-contact injury	Peak speed in training/match	Peak speed in training/match was considered as MSS for individualization process.	Sprint threshold (> 24.9 km/h)	Sprint threshold (> 75% MSS; > 80% MSS; > 85% MSS; > 90% MSS; > 95% MSS)
Ortega-Gálvez et al. [42]	Compare arbitrary and individualized speed thresholds on locomotor demands in matches	40-m linear sprint starting and 30-15 Intermittent Fitness test for MAS	The final velocity achieved in the 30-15 Intermittent Fitness test was considered as MAS for individualization. The peak speed attained in the best 10-m split was considered as MSS.	Moderate (13.1-18.6 km/h); Sprint (20 km/h)	Moderate intensity (68% MAS); High intensity (> 87% MAS); Sprint (80% MSS)
Park et al. [24]	Compare arbitrary and individualized speed thresholds on locomotor demands in matches	Spectral Clustering, k-means and Gaussian mixture model	The algorithms were used to identify velocity zones in each computed half match, while linear-mixed modelling determined generic squad thresholds	High-velocity running (Generic: 4 m/s, Bradley and Vescovi: 3.34 m/s); Very-high velocity running (Generic: 5.5 m/s, Bradley and Vescovi: 4.45 m/s); Sprinting (Generic: 7 m/s, Bradley and Vescovi: 5.56 m/s)	k-means: High-velocity running (1.05 m/s); Very-high velocity running (2.10 m/s); Sprinting (3.60 m/s); Gaussian mixture model: High-velocity running (0.56 m/s); Very-high velocity running (1.53 m/s); Sprinting (3.05 m/s); Spectral Clustering (β = 0.1): High-velocity running (3.46 m/s); Very-high velocity running (5.29 m/s); Sprinting (6.26 m/s); Spectral Clustering (β = 0.01): High-velocity running (3.54 m/s); Very-high velocity running (5.38 m/s); Sprinting (6.30 m/s); Spectral Clustering (β = 0.001): High-velocity running (3.56 m/s); Very-high velocity running (5.39 m/s); Sprinting (6.30 m/s); Spectral Clustering (β = 0): High-velocity running (3.58 m/s); Very-high velocity running (5.41 m/s); Sprinting (6.27 m/s);
Rago et al. [46]	Analyze the relationship between locomotor and physiological demands, while considering arbitrary and individualized speed thresholds in matches.	Yo-Yo intermittent recovery test level 1 and peak speed attained in training sessions.	The final velocity attained in the Yo-Yo intermittent recovery test level 1 was considered for the estimation of the MAS. The peak speed attained in training sessions was considered as the MSS. The ASR was calculated from the difference of MSS and MAS.	Moderate speed running (14.4-19.8 km/h); high-speed running (19.9-25.1 km/h); sprinting (> 25.2 km/h).	Moderate speed running (80-99.9% MAS); high-speed running (100%MAS-29%ASR); sprinting (> 30% ASR).
Rago et al. [14]	Compare arbitrary and individualized speed thresholds on locomotor demands in matches	Yo-Yo intermittent recovery test level 1 and peak speed attained in training sessions.	The final velocity attained in the Yo-Yo intermittent recovery test level 1 was considered for the estimation of the MAS. The peak speed attained in training sessions was considered as the MSS. The ASR was calculated from the difference of MSS and MAS.	Moderate speed running (14.4-19.8 km/h); high-speed running (19.9-25.1 km/h); sprinting (> 25.2 km/h).	Moderate speed running (80-99.9% MAS); high-speed running (100%MAS-29%ASR); sprinting (> 30% ASR).
Reardon et al. [16]	Compare arbitrary and individualized speed thresholds on locomotor demands in matches	Peak speed attained in matches.	The peak speed attained in matches was considered as the MSS.	High speed running (5 m/s2).	High speed running (5 m/s2 divided by the average of MSS of the group).
Scanlan et al. [83]	Compare arbitrary and individualized PlayerLoad thresholds in training sessions.	Peak instantaneous PlayerLoad intensity recorded in training.	The peak instantaneous PlayerLoad intensity was used to individualized threshold.	PlayerLoad zone 1 (0-1 A.U.); PlayerLoad zone 2 (1-2 A.U.); PlayerLoad zone 3 (2-3 A.U.); PlayerLoad zone 4 (3-4 A.U.); PlayerLoad zone 5 (4-6 A.U.); PlayerLoad zone 6 (6-10 A.U.).	PlayerLoad zone 1 (0-10% peak PlayerLoad); PlayerLoad zone 2 (10-20% peak PlayerLoad); PlayerLoad zone 3 (20-30% peak PlayerLoad); PlayerLoad zone 4 (30-40% peak PlayerLoad); PlayerLoad zone 5 (40-60% peak PlayerLoad); PlayerLoad zone 6 (60-100% peak PlayerLoad).
Scott et al. [17]	Determine dose-response relationship between locomotor and physiological demands while use arbitrary and individualized speed thresholds in training sessions.	40-m linear sprint, the modified version of Montreal Track Test (VAM-EVAL) and the Yo-Yo Intermittent Recovery Test level 1	The best peak speed obtained in the splits of 10-m were considered as MSS. The last stage attained at VAM-EVAL and the Yo-Yo Intermittent Recovery Test level 1 were used to estimate the MAS.	High-speed running (12.67 km/h); Very high-speed running (17.82 km/h)	High-speed running (80%MAS at VAM-EVAL; or 80% at Yo-Yo Intermittent Recovery Test level 1; or 50% MSS); Very high-speed running (100%MAS at VAM-EVAL; or 100% MAS at Yo-Yo Intermittent Recovery Test level 1; or 65% MSS)
Scott et al. [47]	Examine the dose-response relationship between match-player demands and ratings of fatigue and soreness, while using arbitrary and individualized thresholds.	40-m linear sprint, and the 30-15 Intermittent Fitness Test	The fastest sprint in splits of 10-m was considered as the MSS. The final velocity of 30-15 Intermittent Fitness Test was estimated as a MAS measure. The ASR was calculated based on the difference between MSS and MAS.	High-speed running (12.5 km/h); Very high-speed running (19.0 km/h); Sprinting (22.5 km/h).	High-speed running (60% MAS; 50% MSS); Very high-speed running (80% MAS; 65% MSS); Sprinting (30% ASR; 80% MSS).
Siegle et al. [54]	Analyze inter-individual differences in the locomotor speed and compare with general approach in match.	Q-Q-Plots	Q-Q-Plots were used to graphical inspection of intersection point.	Walking (qualitative approach); Jogging (qualitative approach); Cruising (qualitative approach); Sprinting (qualitative approach).	Walking/Jogging (intersection point in movement velocity, average: 2.06 m/s2); Jogging-Cruising/sprinting (intersection point in movement velocity, average: 4.53 m/s2).
Taylor et al. [48]	Compare the training load in different age-groups, while using arbitrary and individualized speed thresholds.	30-m linear sprint, and the 30-15 Intermittent Fitness Test	The peak speed at 30-m linear sprint was used as MSS. The final velocity of 30-15 Intermittent Fitness Test was estimated as a MAS measure.	High-speed running (> 19.8 km/h); Sprint running (> 25.2 km/h).	High-speed running (87% MAS); Sprint running (80% MSS).
Taylor et al. [84]	Identify the dose-response relationship between training load measures, while considering arbitrary and individualized speed thresholds.	Incremental treadmill test	The velocities at 2 mmol/L and 4 mmol/L lactate were estimated to individualization of speed thresholds.	High-speed distance (> 15 km/h); Very high-speed distance (> 18 km/h).	High speed distance thresholds (velocity at 4 mmol/L lactate, range: 8.7 to 13.1 km/h)
Taylor et al. [85]	To assess the relationships between external and internal load ratios, while considering arbitrary and individualized speed thresholds.	Incremental treadmill test	The velocities at 2 mmol/L and 4 mmol/L lactate were estimated to individualization of speed thresholds.	High-speed distance (> 15 km/h); Very high-speed distance (> 18 km/h).	High speed distance thresholds (velocity at 4 mmol/L lactate, range: 8.7 to 13.1 km/h)

ASR: anaerobic speed reserve; Aust. Foot.: Australian Football; Comp.: competitive; GPS: Global Positioning System; H: hockey; IU: information unavailable; LPS: local positioning system; M: men; MAS: maximal aerobic speed; MSS: maximal sprint speed; N: number of participants; RCT: Respiratory compensation threshold; UK: United Kingdom; USA: United States of America; W: women.