Coaches’ Perceptions of Factors Driving Training Adaptation: An International Survey

The survey utilised a purposive convenient sample due to the lack of a centralised coaching database needed for probability sampling. Participation was voluntary, and all those who took part were notified they could withdraw at any point. Due to the fundamental nature of the topics explored within the survey there were limited inclusion criteria of currently working with athletes as a coach, being at least 18 years old and being English literate. With no agreed way to determine sample size for surveys, we established ours on the basis of similar studies leading to a minimum sample of 100 [19, 20]. The survey was available online through Microsoft Forms from November 2021 to February 2022 and was distributed via the authors social media accounts (Twitter and Instagram). To try to limit the potential effects of sampling bias, including the overrepresentation of coaches with strong opinions on certain topics, terms such as ‘general adaptation syndrome’ or ‘periodisation’ did not feature in the advertisement of the survey and appeared only in a limited manner within the survey.

This study used a cross-sectional study approach. After surveying the literature, it was determined that no prior survey asked questions that allowed for the exploration of topics that the authors were interested in. Therefore, it was determined that a new survey would need to be created, with an initial survey being developed by the authors. Once an initial survey was established, recent surveys in the literature were consulted to determine best practice validation [21, 22]. To establish both face and informal content validity, the initial survey was trialled with a small group of experienced coaching practitioners qualified to doctoral level (n = 3). The purpose of this was to determine whether the survey properly reflected the relevant literature, and feedback from this process was then used to improve content and clarity. A second round of content analysis combined with piloting was performed on the updated survey specifically focussing on expression of concepts and clarity. For this round, a second group of practitioners representative of the target population (n = 7) but not involved in the initial survey validation was used. On the basis of this feedback, final alterations were made to further refine the survey. The final survey was constructed around three distinct topics that ordinarily would be covered in distinctly separate surveys: (1) factors driving physical training adaptation, (2) ‘fundamentals’ of planning training and (3) the predictability of training adaptations. This merging was done due to issues around recruitment and retention of participants. At the outset it was determined that these separate topics would be merged into one survey but then be separated back out for analysis. In part this was also considered necessary as it would not be possible to coherently cover all the topics in a single article. The authors felt that these circumstances met the criteria set out by the APA for separating a single dataset into multiple publications. Within this article a subset of the data referring to questions focussing on the key drivers of physical training adaptation are presented. The questions discussed are available in the supplementary material but are also given below each figure in the results section. Ethical approval for the survey was obtained from the German Sport University Cologne ethics committee.

Due to the use of convenient sampling, it was decided that we would only present descriptive statistics (in the form of percentage responses, not means or standard deviations) as we could not make any generalisations or inferences to the wider population [23]. Survey responses were exported to Microsoft Excel [24] and anonymised, missing data checks were performed and then the responses were analysed in comparison with the literature. A partial summary of the data is presented in text, with the rest available in the supplementary material.

On closing of the survey, 108 responses had been collected of which 106 agreed to complete the survey. The demographic details of the participants can be seen in Table 1. Participants were predominantly male (92%) with a high level of formal education (60% postgraduate) compared with other studies [20, 25]. The majority (84%) held a coaching qualification. Participants worked with team and/or individual sports at a variety of levels.

Most participants agreed or strongly agreed that athletes with similar training experiences will respond differently to the same training protocol (Fig. 1). Nevertheless, very few training studies consider or report individual participant data. Indeed most investigations treat individual variation as unavoidable but largely irrelevant noise and seek to minimise its effect through methodological and analytical techniques [26, 27]. However, a recent study, starting from the premise that coaches are likely most interested in applications at an individual level, looked to examine the extent to which group-level results could be generalised to individual athletes [10]. After analysing two seasons worth of load and recovery data (11,055 observations), collected from 82 youth academy football players at a major league club (Eredivisie league), the authors reported different correlations between load and recovery at both a group and individual level. The importance of these results is that they suggest that group-based results do not generalise to individuals. Therefore, employing recommendations based on grouped responses is a suboptimal, or even erroneous, training prescription strategy. As further illustration, Morin et al. [8] demonstrated that sprinters, given the same training protocol, exhibited clear individualisation of performance increases across a range of related metrics, such as 5 and 30 m sprint times. Furthermore individualisation also effected the time for results to be realised post-intervention [8].

The adoption of the biomedical model as the basis for research within training theory means that physical training is the primary source for driving physical adaptation. The effect of this on research is that everything else can be considered a confounding factor that once removed will reveal the “reliability of training effects” [26]. Despite this, in this survey, over a quarter (28%) of coaches agreed that physical training was the most important influence on sport performance, with more (39%) disagreeing. The remaining one-third (33%) were neutral. Furthermore, participants also responded, overwhelmingly (99%), that non-physical factors, such as psychological stress, influence physical training responses. This opinion appears in line with the wider scientific literature illustrating that non-physical factors, such as psychological stress, can dramatically influence general health and physiological outcomes [28]. This poses a problem to the already described approach taken within a large part of the training specific literature as non-physical factors undoubtedly play a role and their effects cannot be separated from physical factors.

Coaches’ perspectives on the importance of non-physical factors were addressed by asking participants to rate how different factors modified an athlete’s ability to physically adapt to a training plan. Interestingly, four non-physical training influences received the greatest ratings of ‘absolutely essential’, even more than physical training (33%) or genetics factors (23%) [coach–athlete relationship (56%), life stress (41%), athletes’ belief in the plan (37%), psychological and emotional stress (35%)].

Athlete’s belief in the plan was perceived as either ‘absolutely essential’ (37%) or ‘very important’ (62%) by 99% of participants, more than any other factor. Belief in the plan can be thought of as a series of predictions about future events which are formed by an array of factors that include suggestion, observational learning, conditioning and personal relationships like those between coach and athlete [29]. This is sometimes referred to as the placebo effect, which can have very real and powerful effects on a person’s physiology [29].

Of all the factors listed that could modify how well athletes physically adapt to the training plan it was the ‘coach–athlete relationship’ that received the highest rating of ‘absolutely essential’ (56%) by the coaches surveyed. This finding echoes research in medical contexts. As illustration, a recent meta-analysis examining whether patients’ ‘trust’ in their health care professional was associated with health outcomes found that those with higher ratings of trust reported fewer symptoms, demonstrated better adherence to treatments and had higher perceived quality of life [30]. Nevertheless, the perceived relevance of the coach–athlete relationship is not reflected in either conventional training research or theory [31].

Psychological and emotional stress and life stress were considered ‘absolutely essential’ by 35% and 41% of the participants, respectively. The relevance of ‘stress’ has been discussed in the training adaptation literature as well as that of sports injury occurrence and rehabilitation efficacy [13, 32, 33]. It is interesting to note that life stress received a higher rating even though it could be considered a subset of psychological and emotional stress. Regardless, both factors have been shown to have crucial and inseparable impact on the adaptation process [12‐14]. An example of this can be seen in Stults-Kolehmainen et al. 2014 study looking at the effect of chronic mental stress on recovery after resistance training [13]. The authors reported that “chronic mental stress has a measurable impact on the rate of functional muscle recovery from strenuous resistance training over a 4-day period. Specifically, higher levels of stress resulted in lower recovery curves and, conversely, lower levels of stress were associated with superior levels of recovery.” (page 8).

Nevertheless, stress outside that of a ‘physical’ nature generally remains ignored within the conventional periodisation literature. This conception of stress, which is grounded in the work of Hans Selye, views these aspects as merely ‘conditioning factors’, a concept which is now outdated. A more modern understanding is that stress (no matter the source) is mediated by the brain as it perceives whether an event is threatening and determines the appropriate behavioural and physiological response [34].

Notably, coaches’ practical perspectives appear in conflict with the positions of major coach education organisations. As an example, the Essentials of Strength Training and Conditioning [1], published by the National Strength and Conditioning Association (NSCA) and “the primary resource to rely on for CSCS [Certified Strength & Conditioning Specialist] exam preparation” [35], acknowledges that various factors exert an influence on training adaptation. Nevertheless, when discussing how to plan a training session or programme, no non-physical factors, such as those highlighted in this survey, are considered.

As illustration, previously the importance of the coach–athlete relationships has been suggested. Jowett and Cockerill, for example, suggested that coach education programmes should not focus only on providing information relevant to physical, technical and tactical skills, but also provide education relating to the fostering of effective relationships with athletes [36]. Nevertheless, the inclusion of non-physical factors within physical training theory, as exemplified by the NSCA’s Essentials of Strength and Conditioning omission of such considerations, remains sparse, at best [1].

A strict biomedical interpretation of training adaptation, which assumes a mechanistic, and therefore predictable, relationship between conducted training and physiological adaptation, is still pervasive within the literature [2, 11]. Nevertheless, this survey suggests that many practising coaches may hold contrary beliefs given the rated importance of multiple non-physical factors. Therefore, it might be beneficial for future studies to look to other research paradigms that integrate these factors. An example of this could be the biopsychosocial model [3]. It has gained increasing acceptance in medicine due to its acknowledgement of the integrated role of physiological, psychological and social factors in health.

From a methodological perspective given the inter-individual difference in response to training stimuli, studies should report individual responses, either within the study results or as appendices available to the interested reader [37, 38]. Furthermore, to remain practically relevant, training science should collate, consider and, where appropriate, integrate the perspectives of practitioners who plan and deliver athletic training plans.

This is the first global survey to examine coaches’ opinions on a range of factors that drive physical training adaptation. Despite this there are limitations that need to be addressed. As previously mentioned, probability sampling was not used in this study, which carries certain limitations with it such as not being able to make statistical inferences and therefore generalise the results from the current sample to the entire coaching population or specific subpopulations [19, 39]. It is worth noting, though, that the bar is quite high for statistical inferences to be made [40]. However, whilst this is a limitation, the novelty of the survey and its exploratory nature does give insight into some coaches’ perspectives on these important topics. Due to its exploratory nature, further work is needed. With no surveys discussing these topics, the questions were specifically customised. This brings both strengths and weaknesses. Whilst bespoke questions provided novel insights, some questions could be strengthened by an increase in detail or follow-up questions. These would be worthwhile pursuing in future research. Similarly, and inevitably, despite striving for clear expression, some questions may have been misinterpreted [39]. Furthermore, and reflecting a widespread gender bias within performance coaching, only 8% of respondents were female. Finally, this survey was advertised and delivered in English only, and was subsequently unduly biased towards English-speaking participants.

Whether and how coaches integrate non-physical training influences into coaching practice and training plans remains undocumented. Accordingly, investigations detailing coaches’ action and implementation of these considerations, within training contexts, would be beneficial. Similarly, given the neglect of non-physical factors within the physical training literature, it would be interesting to understand how coaches came to hold these perspectives. Finally, the potential relevance of coaches country and/or cultural influences in shaping their beliefs and perspectives around concepts of training adaptation would also be informative [41, 42].