Training strategies of 10,074 athletes from 121 countries based on human development index in early COVID-19 lockdown

Participants

Participants provided informed consent, and the study received the ethical approval from the University of Melbourne (HREC No. 2056955). This research was conducted in accordance with the principles outlined in the Declaration of Helsinki. Furthermore, the principles of the General Data Protection Regulation (gdpr-info.eu) were followed to preserve confidentiality of participants during the data collection. All participants were informed of their freedom to withdraw or rescind their agreement to the data collection at will.

The eligibility criteria were: (i) individuals aged ≥ 18-years-old with or without a disability; (ii) had experienced ≥ 2 consecutive weeks of the early lockdown (March to June 2020); (iii) had not missed training for ≥ 7 days due to illness and/or injury during the survey period; and (iv) experienced a ‘medium to high’ lockdown severity level, defined as meeting one or more of the following conditions: (a) movement was limited for essential supplies and groceries only; (b) access limitations to public exercise facilities were imposed (i.e., limited access, or closure of recreational places such as parks or open spaces were not allowed and/or time/capacity limited); and (c) closure of public and private training facilities, at colleges, clubs, institutions. Responses from 10,074 athletes from 18 to 76 years old (self-described as 5290 amateur and 4787 professional and semi professional athletes from 121 countries) were included in statistical analyses.

Training practices before and during the first 100 days of lockdown

Both amateur and professional athletes (female and male) reported a decrease in training frequency (− 36% for all amateurs and 39% for all elite), duration (− 33% for all amateurs and 33% for all elite) and quantity (− 54% for all amateurs and 56% for all elite) compared to pre-lockdown (Table ​(Table2).2). However, no significant time effect (before vs during lockdown) and HDI interactions were observed for training frequency.

Session duration decreased by 33% and 33% in amateurs and professional groups, respectively. Variations in session duration across time (before and during lockdown), gender, and level of performance indicated that as the HDI increased, there was a corresponding decrease in training duration (before and during lockdown) (Table ​(Table2).2). Post-hoc tests revealed that training session durations were longer in very high HDI when compared to high and low-medium HDI levels (before lockdown). Similarly, before lockdown, post-hoc tests revealed a longer session duration in very high HDI level (among amateur and professional) athletes when compared to high and low-medium HDI countries (Table ​(Table22).

Training frequency decreased by ~ 37% and 40% for amateurs and professional groups, respectively. Post-hoc tests revealed that female athletes reported a higher frequency of training both before and during lockdown in very high HDI countries when compared to high HDI countries (Table ​(Table2).2). Similarly, post-hoc tests identified that male athletes reported a higher frequency of training during lockdown in very high HDI countries than those in high HDI countries.

Overall training quantity decreased by 54% and 57% in amateur and professional groups, respectively. Post-hoc tests revealed that both female and male groups reported a higher training quantity before and during lockdown in very high HDI than low-medium HDI countries. Post-hoc tests also showed that both females and males reported higher training quantity before and during lockdown in very high HDI countries when compared to high HDI countries.

Amateur athletes reported lower training frequency and quantity when compared to professionals (Table ​(Table2).2). Between amateurs and professionals, no differences were observed for training duration in females from high HDI countries, male training duration in high and very high HDI countries, and quantity of training in males of high HDI countries during the enforced lockdowns (Table ​(Table22).

Authority rules and training

During the lockdowns, athletes adjusted their training approaches in accordance with regulations set by the authorities in their respective countries. In countries with low-medium HDIs, athletes were primarily limited to home-based training focused on technical skill and mobility exercises. In contrast, athletes in high HDI countries had more opportunities to exercise around the housing area (residences), emphasizing general fitness and health, flexibility, muscle endurance, strength and power, and muscle balance. Athletes in very high HDI countries were able to access even more diverse options, like running or training in parks, stadiums, cycling, and hiking in non-public facilities (i.e., permitted by local authorities). These athletes could also more often receive or borrow training equipment, and/or gain access to a gymnasium, or sport training facility during lockdown (Table ​(Table1).1). Accordingly, Czech et al.¹⁷ showed that a more stringent anti-COVID-19 policy was related to greater declines in human mobility, and that HDI levels was an important driving factor mediating the magnitude of human mobility changes during COVID-19.

During the lockdown some elite athletes reported to receive training equipment to help them train at home while under lockdown, through their clubs or sponsors¹⁸. Athletes from higher HDI locations generally experienced more flexible training opportunities, including access to a broader range of locations for training sessions and specialized training equipment. Both the locations and training purpose during lockdown were strongly influenced by the HDI level (Table ​(Table1).1). Moreover, professional athletes in high and very high HDI countries had a greater opportunity for diverse training purposes (Table ​(Table1).1). These data shows that there was a substantial amount of HDI-related inequality for athletes during the early COVID-19 pandemic’ lockdown that could have affected both physical, social and mental health in athletes.

Training behaviors and performance level

We revealed a similar decline in key training variables, across duration, frequency and the product of these variables, training quantity, irrespective of HDI and performance levels (Table ​(Table2).2). The decline in training observed in athletes during lockdown described herein (Table ​(Table22 and Fig. 1) has been reported in the general population^19–21 and in active people²² or athletes^8,9. While individuals in Europe and North America showed some recovery, their “step count data”, in early 2022 movement remained 10% lower than global prepandemic baseline (5600 steps per day) with regional variation²⁰. Some early studies neglected differences in HDI levels, potentially overestimating the influence of a country’s healthcare standard, education, and socio-economic environment¹⁷. Moreover, limited data are available on exercise variables such as frequency, duration, quantity and intensity during lockdowns, which are the key factors in meeting moderate to vigourous physical activity international recommendations¹³. Thus, the current study (HDI influences) adds a new dimension to the existing literature, which primarily suggests that high-level, as well as professional athletes faced minimal disruption (compared to low-level, and amateur athletes) in their training routines during lockdowns^{8,9, 23}.

Between amateurs and professionals, no differences were observed for training duration in females from high HDI countries.

We observed that the quantity of training during lockdown was strongly dependent on the HDI level across time (before and during lockdown) in male athletes. However, no differences were observed in females regardless of HDI level (Table ​(Table2)2) and training status. While we observed that lockdown and HDI impacted training duration in both professional and amateur male athletes, this was not the case in amateur and professional females (Table ​(Table2).2). Professional female athletes in high HDI countries, were particularly vulnerable to reduced frequency and quantity of training. This observation may be attributable to the demand of work (mainly for amateur women), as well as family responsibilities (for amateur and professional female athletes), which might have affected their training time and motivation (Table ​(Table22)^5,24. Moreover, differences in financial ressources and support available for professionnel women could have affected their daily life and as a consequence, their training during the lockdown. With regards to gender difference, earlier studies have also reported a notable disparity in training between genders in training, such as fewer weekly training days and less total training hours in female athletes compared to their male counterparts²⁵. The challenges faced by female athletes, including those living in high HDI countries, highlights the need for specific considerations related to gender in future health policies and guidelines.

Maintenance or increase of training during lockdown

Using logistic regression and factor based on HDI levels, we identified the main factors that had an impact on the training maintainance during lockdown (Table ​(Table3;3; supplemental material 1). In low-medium HDI countries, the focus of “specific training” category (Table ​(Table2)2) was on body weight exercises, long endurance, and innovative training. Athletes were compelled to find new ways of training, typically in isolation, and frequently through online platforms, due to lockdown measures and cessation of traditional (regular) training, which involves communications between athletes and coaches⁸. In high and very high HDI countries, the focus shifted to weightlifting or cardiovascular in the “types of exercises” category (Table ​(Table2,2, Fig. 2), along with speed and interval training. These choices provide evidence of adaptable training strategies during lockdown due to athletes’ training knowledge and their ability to apply the training⁸. According to a mini review, typical home training (for team-sport athletes) during lockdowns consisted of about 5 weekly sessions lasting 45 to 90 min each, and primarily focused on muscular strength and endurance²⁶. These practices resulted in decreased VO₂max, slower sprint times, and inconsistent (negative/positive) changes in countermovement jump height²⁶. Other studies have also indicated that a country’s socio-economic development largely influenced training behaviors^5,20. Combined with the level of training knowledge, athletes could explore innovative ways to train beyond body weight exercises and long endurance training, as observed in global population⁶.

Somewhat surprisingly, professional athletes reported difficulties in maintaining exercise quantity in low-medium and high HDI countries, but this was not entirely the case in very high HDI countries (Table ​(Table3).3). Unlike in very high HDI countries, restrictions on exercise locations and lockdown durations had a negative impact in lower HDI countries that might relate to the socio-economic environment of these countries^5,20. However, research on how macroeconomic factors (e.g., HDI) affect training practices, particularly during the COVID-19 crisis, is notably lacking. In the current study, athletes demonstrated adaptability in exercise regimens based on their socioeconomic and educational backgrounds. The specific strategies adopted by athletes may be applicable to wider population at similar HDI levels, incuding individuals with diverse backgrounds and health conditions (e.g., youth, old, disability or chronic disease, pregnant women), and can inform public policies and guidelines. Tailored recommendations, including digitally-mediated training⁸, can be effective at combating inactivity across all HDI levels, despite the challenges in implementation⁶. In addition, “bubble” training camps may be implemented to allow regular training with teammates (supported by coaches and performance support staff)^27,28.

We thank all athletes who participated in this project, and colleagues and coaches who assisted us with data collection.