Ok, depois de algumas tentativas e erros e alguma ajuda de @ Rizier123, aqui está a resposta:
html na página do formulário
Por uma questão de clareza, eu estava tentando descobrir como adicionar várias matrizes de dados ao meu banco de dados. Então, na página de formulário dinâmico, tenho entradas semelhantes a:
<p>Location: <input type='text' name='location[]' > </p>
Processando o formulário e inserindo os dados no banco de dados
Primeiro, mudei de mysqli para PDO, depois executei com o seguinte código:
try {
$sql = "INSERT INTO location_info (`department`, `participant`, `activity`, `location`, `rec_injuries`, `rec_injuries_timeframe`, `non_rec_injuries`, `non_rec_injuries_timeframe`, `competitor`, `cost_per_pair`, `usage_rate`, `leakage`, `cost_of_productivity`, `non_rec_impact`, `non_rec_sprain`, `non_rec_puncture`, `non_rec_dermatitis`, `non_rec_infection`, `non_rec_burns`, `non_rec_cuts`, `rec_impact`, `rec_sprain`, `rec_puncture`, `rec_dermatitis`, `rec_infection`, `rec_burns`, `rec_cuts`, `condition`, `general_id`)
VALUES (:department, :participant, :activity, :location, :rec_injuries, :rec_injuries_timeframe, :non_rec_injuries, :non_rec_injuries_timeframe, :competitor, :cost_per_pair, :usage_rate, :leakage, :cost_of_productivity,:non_rec_impact, :non_rec_sprain, :non_rec_puncture, :non_rec_dermatitis, :non_rec_infection, :non_rec_burns, :non_rec_cuts, :rec_impact, :rec_sprain, :rec_puncture, :rec_dermatitis, :rec_infection, :rec_burns, :rec_cuts, :condition, '{$id}')";
$stmt = $db->prepare($sql);
for($i = 0, $l = count($_POST["department_name"]); $i < $l; $i++) {
$loc_info = array(':department' => $_POST["department_name"][$i],
':participant' => $_POST["participant_name"][$i],
':activity' => $_POST["activity"][$i],
':location' => $_POST["location"][$i],
':rec_injuries' => $_POST["injuries"][$i],
':rec_injuries_timeframe' => $_POST["injury_time_frame"][$i],
':non_rec_injuries' => $_POST["non_rec_injuries"][$i],
':non_rec_injuries_timeframe' => $_POST["non_rec_injury_timeframe"][$i],
':competitor' => $_POST["competitor"][$i],
':cost_per_pair' => $_POST["cost_per_pair"][$i],
':usage_rate' => $_POST["usage_rate"][$i],
':leakage' => $_POST["leakage"][$i],
':cost_of_productivity' => $_POST["cost_of_productivity"][$i],
':non_rec_impact' => $_POST["non_rec_impact"][$i],
':non_rec_sprain' => $_POST["non_rec_sprain"][$i],
':non_rec_puncture' => $_POST["non_rec_puncture"][$i],
':non_rec_dermatitis' => $_POST["non_rec_dermatitis"][$i],
':non_rec_infection' => $_POST["non_rec_infection"][$i],
':non_rec_burns' => $_POST["non_rec_burns"][$i],
':non_rec_cuts' => $_POST["non_rec_cuts"][$i],
':rec_impact' => $_POST["impact"][$i],
':rec_sprain' => $_POST["sprain"][$i],
':rec_puncture' => $_POST["puncture"][$i],
':rec_dermatitis' => $_POST["dermatitis"][$i],
':rec_infection' => $_POST["infection"][$i],
':rec_burns' => $_POST["burns"][$i],
':rec_cuts' => $_POST["cuts"][$i],
':condition' => $_POST["condition"][$i] );
$stmt->execute($loc_info);
}