Arne Nieuwenhuys

Dutch police officers’ preparation and performance of their arrest and self-defence skills: A questionnaire study

We investigated how Dutch police officers perceive their preparation for arrest and self-defence skills (ASDS) and their ability to manage violence on duty. Furthermore, we assessed whether additional experience (i.e., by having encountered violence on duty or by practicing martial arts) and self-perceived anxiety have an influence on these perceptions. Results of an online questionnaire (n = 922) showed that having additional experience was associated with self-perceived better performance. Officers who experience anxiety more often, on the other hand, reported more problems. Although most officers report sufficiently effective performance on duty, they, especially those with additional experience, feel that training frequency is too low and that the currently taught ASDS are only moderately usable (at least with the current amount of training). Based on the results, we suggest that increasing officers ASDS experience, teaching officers to perform with high anxiety, or reconsidering the taught skills, may be necessary to further improve performance of police officers on duty.

Self-reported sleep quantity, quality and sleep hygiene in elite athletes

Sleep is essential for recovery and performance in elite athletes. While actigraphy‐based studies revealed suboptimal sleep in athletes, information on their subjective experience of sleep is scarce. Relatively unexplored is also the extent to which athletes’ sleep is adversely affected by environmental conditions and daytime behaviours, that is sleep hygiene. This study aimed to provide insight in sleep quantity, quality and its putative association with sleep hygiene. Participants were 98 elite (youth) athletes competing at the highest (inter‐)national level. Sleep quantity, quality and sleep hygiene were assessed once covering a 1‐month period by using established (sub)clinical questionnaires, and repeatedly during 7 consecutive days. Sleep quality was generally healthy, although 41% of all athletes could be classified as ‘poor sleeper’, and 12% were identified as having a sleep disorder. Daily self‐monitoring revealed sleep durations of 8:11 ± 0:45 h, but elevated wake after sleep onset of 13 ± 19 min. Sleep quality, feeling refreshed, and morning vigor were moderate at best. Regarding sleep hygiene, general measures revealed irregular sleep–wake patterns, psychological strain and activating pre‐sleep behaviours. At the daily level, blue‐light exposure and late‐evening consumption of heavy meals were frequently reported. General sleep hygiene revealed significant associations with sleep quality (0.45 < r > 0.50; P < 0.001). Results indicate that there is ample room for optimization, specifically in onset latency and in wake after sleep onset. Subtle improvements in sleep seem possible, and optimizing sleep hygiene, such as regular sleep–wake patterns and reducing psychological strain, may facilitate this sleep upgrading process.

Persistence of threat-induced errors in police officers' shooting decisions

This study tested whether threat-induced errors in police officers shooting decisions may be prevented through practice. Using a video-based test, 57 Police officers executed shooting responses against a suspect who rapidly appeared with (shoot) or without (dont shoot) a firearm. Threat was manipulated by switching on (high-threat) or switching off (low-threat) a shootback canon that could fire small plastic bullets at the officers. After an initial pretest, officers were divided over four different practice groups and practiced their shooting decisions for three consecutive weeks. Effects of practice were evaluated on a posttest. On the pretest, all groups experienced more anxiety and executed more false-positive responses under high-threat. Despite practice, these effects persisted on the posttest and remained equally strong for all practice groups. It is concluded that the impact of threat on police officers shooting decisions is robust and may be hard to prevent within the limits of available practice.

Decision-related action orientation predicts police officers' shooting performance under pressure

ABSTRACT Background and Objectives: We aimed to test whether police officers’ trait self-control strength decreases negative effects of high pressure (HP) on state anxiety, shooting behavior, and shooting performance. Design and Methods: Forty-two officers performed a shooting test under both high and low-pressure (LP) conditions. Self-control strength was assessed with the decision-related action orientation (AOD) scale of the Action Control Scale (ACS-90). Effects of AOD on perceived anxiety, heart rate, shooting time, and shot accuracy were estimated and controlled for those of other individual difference measures (i.e. age, police working experience, trait anxiety, and threat-related action orientation). Results: After controlling for baseline values in the LP condition as well as the other individual difference measures, AOD significantly predicted shot accuracy in the HP condition. Conclusions: Results suggest that trait self-control strength in the form of AOD helps officers cope with anxiety and maintain perceptual-motor performance under HP.

Train hard, sleep well? Perceived training load, sleep quantity and sleep stage distribution in elite level athletes

OBJECTIVESnSleep is essential for recovery and performance in elite athletes. While it is generally assumed that exercise benefits sleep, high training load may jeopardize sleep and hence limit adequate recovery. To examine this, the current study assessed objective sleep quantity and sleep stage distributions in elite athletes and calculated their association with perceived training load.nnnDESIGNnMixed-methods.nnnMETHODSnPerceived training load, actigraphy and one-channel EEG recordings were collected among 98 elite athletes during 7 consecutive days of regular training.nnnRESULTSnActigraphy revealed total sleep durations of 7:50±1:08h, sleep onset latencies of 13±15min, wake after sleep onset of 33±17min and sleep efficiencies of 88±5%. Distribution of sleep stages indicated 51±9% light sleep, 21±8% deep sleep, and 27±7% REM sleep. On average, perceived training load was 5.40±2.50 (scale 1-10), showing large daily variability. Mixed-effects models revealed no alteration in sleep quantity or sleep stage distributions as a function of day-to-day variation in preceding training load (all ps>.05).nnnCONCLUSIONSnResults indicate healthy sleep durations, but elevated wake after sleep onset, suggesting a potential need for sleep optimization. Large proportions of deep sleep potentially reflect an elevated recovery need. With sleep quantity and sleep stage distributions remaining irresponsive to variations in perceived training load, it is questionable whether athletes current sleep provides sufficient recovery after strenuous exercise.

Anxiety and performance: Perceptual-motor behavior in high-pressure contexts

When the pressure is on and anxiety levels increase it is not easy to perform well. In search of mechanisms explaining the anxiety-performance relationship, we revisit the integrated model of anxiety and perceptual-motor performance (Nieuwenhuys and Oudejans, 2012) and provide a critical review of contemporary literature. While there is increasing evidence that changes in attentional control affect the execution of goal-directed action, based on our model and emerging evidence from different scientific disciplines, we argue for a more integrated, process-based approach. That is, anxiety can affect performance on different levels of operational control (i.e., attentional, interpretational, physical) and - moving beyond the execution of action - have implications for different aspects of perceptual-motor behavior, including situational awareness and decision making.

The impact of personality traits and professional experience on police officers’ shooting performance under pressure

Abstract We explored the impact of professional experience and personality on police officers’ shooting performance under pressure. We recruited: (1) regular officers, (2) officers wanting to join a specialised arrest unit (AU) (expected to possess more stress-resistant traits; pre-AU) and (3) officers from this unit (expected to also possess more professional experience; AU) (all male). In Phase 1, we determined personality traits and experience. In Phase 2, state anxiety, shot accuracy, decision-making (shoot/don’t shoot), movement speed and gaze behaviour were measured while officers performed a shooting test under low and high pressure. Results indicate minimal differences in personality among groups and superior performance of AU officers. Regression analyses showed that state anxiety and shooting performance under high pressure were first predicted by AU experience and second by certain personality traits. Results suggest that although personality traits attenuate the impact of high pressure, it is relevant experience that secures effective performance under pressure. Practitioner Summary: To obtain information for police selection and training purposes, we let officers who differed in personality and experience execute a shooting test under low and high pressure. Outcomes indicate that experience affected anxiety and performance most strongly, while personality traits of thrill- and adventure-seeking and self-control also had an effect.

Fatigue experiences in competitive soccer: Development during matches and the impact of general performance capacity

ABSTRACT Background: Fatigue as a result of prolonged activity may increase injury risk and decrease performance. Purpose: To provide insight in the development of fatigue experiences during soccer matches and the extent to which general performance capacity (i.e. overall physical fitness, psychological fitness, and recovery) contributes to these fatigue experiences. Methods: 450 Soccer players from the highest divisions in the Netherlands completed a questionnaire to assess (a) fatigue experiences (feeling tired, physically exhausted, not fit, weak, and mentally exhausted: not at all [1] – very much [7]) during a typical match; and (b) subjective indices of general performance capacity (i.e. general capacity to handle workload). Results: On average, fatigue levels were reported to be moderate. Fatigue increased primarily during the second half of the match and only a small decrease in fatigue was observed during half time. Generally, higher intensity fatigue experiences were reported by attackers than defenders. Regression analyses showed that players’ general performance capacity explained a substantial part of fatigue at the start of a match and also predicted the development of fatigue experiences during a match, with low performance capacity being associated with higher baseline levels of fatigue and a steeper increase in fatigue over time. Conclusions: The observed association between players’ general performance capacity and their fatigue levels during matches suggests that periodic screening of general performance capacity can be informative with regard to the employability of players across different stages of match-play and as such, aid in reducing injury risk and increasing performance.

Effects of fatigue on interception decisions in soccer

In competitive soccer, match-induced fatigue is a common phenomenon that may negatively influence performance. Focusing on decision-making, the current study experimentally tested the impact of fatigue on players’ interception decisions and, in doing so, also took into account potential effects on physical capacity and motivation. Using a counterbalanced pretest–posttest design, 30 well-trained amateur soccer players were tested in a fatigued state vs. a non-fatigued control state (i.e. after performing a simulated soccer match and after watching soccer on television). Before and after both protocols, players performed a sprint test and an interception test in which they were instructed to either intercept or not intercept passes of different speeds. Dependent variables included physical capacity (i.e. maximal sprint capacity), motivation to intercept, decisions to intercept, and success rate of interceptions. Results showed that motivation to intercept but not sprint capacity was negatively affected by fatigue. Despite changes in motivation, fatigue did not significantly affect the number of interception attempts or the success rate of interceptions. In conclusion, findings suggest that match-induced fatigue reduces players’ self-reported motivation to engage in effortful actions (i.e. interception attempts) but does not necessarily affect objective (maximal) physical capacity and decision-making.

Sitting duck or scaredy-cat?: Effects of shot execution strategy on anxiety and police officers’ shooting performance under high threat

Purpose nLaw enforcement may require police officers to inhibit intuitive responses to high threat and thereby affect their emotional reaction and operational effectiveness. Upon this premise, the current study reports two experiments which compare the impact of two relevant shot execution strategies on police officers’ shooting performance under high threat, including (1) fire at an armed assailant and then step away from the assailants line of fire (‘fire-step’) or (2) step away from the assailants line of fire and then fire (‘step-fire’). n nMethod nIn Experiment 1, 15 experienced police officers performed both shot execution strategies against a stationary assailant who occasionally shot back with coloured soap cartridges (high threat), while we measured their state anxiety, movement times and shot accuracy. In Experiment 2, the same 15 officers remained stationary and fired at the assailant who now performed both shot execution strategies in random order, thereby providing an indication of the risk (i.e., chance to get hit) associated with performing either strategy. n nResults nExperiment 1 showed that officers preferred using the step-fire strategy and that using this strategy resulted in lower levels of anxiety, increased time for aiming and more accurate shooting than the fire-step strategy. Experiment 2, however, indicated that the step-fire strategy also increases ones chance of getting hit. n nConclusions nFindings suggest that inhibition of preferred responses under high threat (as in the fire-step strategy) may increase state anxiety and negatively affect shooting performance in police officers. Future work is needed to reveal underlying mechanisms and explore implications for practice.